file system and EFI improvments

[Batcastle]

• Change default root and home partition file systems to btrfs
• Increase default size of EFI partition to 500 MB to allow storage of more kernel stubs and initramfs images
• Fix #67
• Prevent removal of systemd-boot-manager on EFI during installation
• various minor code optimizations and refactorizations

[pep8speaks]

Hello @Batcastle! Thanks for opening this PR. We checked the lines you've touched for PEP 8 issues, and found:

• In the file usr/share/system-installer/UI/main.py:

Line 38:1: E402 module level import not at top of file Line 64:80: E501 line too long (80 > 79 characters) Line 66:80: E501 line too long (82 > 79 characters) Line 115:80: E501 line too long (80 > 79 characters) Line 125:80: E501 line too long (80 > 79 characters) Line 128:80: E501 line too long (80 > 79 characters) Line 131:80: E501 line too long (83 > 79 characters) Line 158:80: E501 line too long (98 > 79 characters) Line 471:80: E501 line too long (84 > 79 characters) Line 512:80: E501 line too long (80 > 79 characters) Line 552:80: E501 line too long (89 > 79 characters) Line 553:80: E501 line too long (100 > 79 characters) Line 579:80: E501 line too long (84 > 79 characters) Line 662:80: E501 line too long (85 > 79 characters) Line 678:80: E501 line too long (80 > 79 characters) Line 710:80: E501 line too long (80 > 79 characters) Line 719:80: E501 line too long (91 > 79 characters) Line 793:80: E501 line too long (85 > 79 characters) Line 800:80: E501 line too long (81 > 79 characters) Line 806:80: E501 line too long (90 > 79 characters) Line 816:80: E501 line too long (98 > 79 characters) Line 839:80: E501 line too long (85 > 79 characters) Line 860:80: E501 line too long (96 > 79 characters) Line 907:80: E501 line too long (152 > 79 characters) Line 974:80: E501 line too long (91 > 79 characters) Line 977:80: E501 line too long (107 > 79 characters) Line 983:80: E501 line too long (94 > 79 characters) Line 985:80: E501 line too long (100 > 79 characters) Line 988:80: E501 line too long (87 > 79 characters) Line 990:80: E501 line too long (115 > 79 characters) Line 992:43: E711 comparison to None should be 'if cond is not None:' Line 993:80: E501 line too long (82 > 79 characters) Line 997:80: E501 line too long (89 > 79 characters) Line 999:80: E501 line too long (89 > 79 characters) Line 1005:80: E501 line too long (85 > 79 characters) Line 1025:80: E501 line too long (103 > 79 characters) Line 1049:5: E303 too many blank lines (2) Line 1082:5: E303 too many blank lines (2) Line 1086:80: E501 line too long (88 > 79 characters) Line 1203:80: E501 line too long (83 > 79 characters) Line 1213:80: E501 line too long (94 > 79 characters) Line 1225:80: E501 line too long (83 > 79 characters) Line 1227:80: E501 line too long (91 > 79 characters) Line 1237:16: E126 continuation line over-indented for hanging indent Line 1238:16: E126 continuation line over-indented for hanging indent Line 1240:80: E501 line too long (94 > 79 characters) Line 1252:80: E501 line too long (87 > 79 characters) Line 1276:80: E501 line too long (86 > 79 characters) Line 1285:80: E501 line too long (86 > 79 characters) Line 1289:9: E122 continuation line missing indentation or outdented Line 1289:80: E501 line too long (121 > 79 characters) Line 1290:80: E501 line too long (129 > 79 characters) Line 1303:80: E501 line too long (80 > 79 characters) Line 1304:80: E501 line too long (154 > 79 characters) Line 1342:80: E501 line too long (89 > 79 characters) Line 1368:80: E501 line too long (81 > 79 characters) Line 1452:80: E501 line too long (83 > 79 characters) Line 1517:80: E501 line too long (83 > 79 characters) Line 1541:80: E501 line too long (93 > 79 characters) Line 1674:13: E124 closing bracket does not match visual indentation Line 1675:18: E124 closing bracket does not match visual indentation Line 1676:23: E124 closing bracket does not match visual indentation Line 1677:28: E124 closing bracket does not match visual indentation

• In the file usr/share/system-installer/check_kernel_versions.py:

Line 87:80: E501 line too long (92 > 79 characters) Line 88:80: E501 line too long (93 > 79 characters)

• In the file usr/share/system-installer/engine.py:

Line 106:80: E501 line too long (81 > 79 characters) Line 111:80: E501 line too long (82 > 79 characters) Line 113:80: E501 line too long (80 > 79 characters) Line 114:30: E128 continuation line under-indented for visual indent Line 115:80: E501 line too long (95 > 79 characters) Line 122:80: E501 line too long (87 > 79 characters) Line 143:22: E128 continuation line under-indented for visual indent Line 151:22: E128 continuation line under-indented for visual indent Line 153:80: E501 line too long (100 > 79 characters)

• In the file usr/share/system-installer/modules/master.py:

Line 204:80: E501 line too long (83 > 79 characters) Line 207:80: E501 line too long (82 > 79 characters) Line 218:80: E501 line too long (88 > 79 characters) Line 222:80: E501 line too long (85 > 79 characters) Line 341:80: E501 line too long (80 > 79 characters) Line 344:80: E501 line too long (87 > 79 characters) Line 350:80: E501 line too long (81 > 79 characters) Line 415:80: E501 line too long (127 > 79 characters) Line 416:80: E501 line too long (109 > 79 characters) Line 433:80: E501 line too long (131 > 79 characters) Line 434:80: E501 line too long (119 > 79 characters)

• In the file usr/share/system-installer/modules/verify_install.py:

Line 102:80: E501 line too long (87 > 79 characters)

• In the file usr/share/system-installer/oem/post_install/UI.py:

Line 36:1: E402 module level import not at top of file Line 38:1: E402 module level import not at top of file Line 92:80: E501 line too long (80 > 79 characters) Line 212:80: E501 line too long (83 > 79 characters) Line 242:80: E501 line too long (83 > 79 characters) Line 294:32: E128 continuation line under-indented for visual indent Line 294:32: W503 line break before binary operator Line 408:5: E303 too many blank lines (2) Line 461:68: E231 missing whitespace after ',' Line 490:41: E127 continuation line over-indented for visual indent

• In the file usr/share/system-installer/oem/pre_install.py:

Line 35:1: E402 module level import not at top of file Line 64:80: E501 line too long (80 > 79 characters) Line 67:80: E501 line too long (80 > 79 characters) Line 70:80: E501 line too long (83 > 79 characters) Line 89:80: E501 line too long (89 > 79 characters) Line 90:80: E501 line too long (100 > 79 characters) Line 116:80: E501 line too long (84 > 79 characters) Line 189:80: E501 line too long (85 > 79 characters) Line 205:80: E501 line too long (80 > 79 characters) Line 237:80: E501 line too long (80 > 79 characters) Line 246:80: E501 line too long (91 > 79 characters) Line 320:80: E501 line too long (85 > 79 characters) Line 327:80: E501 line too long (81 > 79 characters) Line 333:80: E501 line too long (90 > 79 characters) Line 343:80: E501 line too long (98 > 79 characters) Line 366:80: E501 line too long (85 > 79 characters) Line 392:80: E501 line too long (91 > 79 characters) Line 395:80: E501 line too long (107 > 79 characters) Line 401:80: E501 line too long (94 > 79 characters) Line 403:80: E501 line too long (100 > 79 characters) Line 406:80: E501 line too long (87 > 79 characters) Line 408:80: E501 line too long (115 > 79 characters) Line 410:43: E711 comparison to None should be 'if cond is not None:' Line 411:80: E501 line too long (82 > 79 characters) Line 415:80: E501 line too long (89 > 79 characters) Line 417:80: E501 line too long (89 > 79 characters) Line 423:80: E501 line too long (85 > 79 characters) Line 443:80: E501 line too long (103 > 79 characters) Line 467:5: E303 too many blank lines (2) Line 564:1: E303 too many blank lines (3)