Setup tests

[ryanfobel]

• [ ] Setup pytest
• [x] KiBot tests:
  • DRC
  • ERC
  • zone fills
• [x] test that there are no spaces in filenames
• [ ] check version number/metadata
• [x] validate BOM

See:

• https://github.com/INTI-CMNB/kibot
• https://github.com/KiCad/kicad-doc/blob/master/src/pcbnew/pcbnew_python_scripting.adoc

[ryanfobel]

Created a new command kh_test that tests all notebooks in the "tests" directory.

Still need to add KiBot tests and add support for pytest.