improve powerline symbols in size 9, 13, 14, 15

[sunaku]

• [ ] Manually clean up the glyphs (they are jagged / garbled) using BDF editor.
• [ ] Save them to a new branch or tag.
• [ ] Overwrite bitmap-font-patcher's glyphs with the manually cleaned up ones.

[sunaku]

Fixed in commit 45802df921db78cc561c178c639c2b9cc4277992.