Kidiff

Added
- Option to skip the test for input files.
Useful to compare from cache.
- Allow to compare two multi-page schematics even when their base name is
different.

Changed
- When comparing multiple sheets using the SVG mode the displayed name of the
sheet is like the sheet path displayed by KiCad

Added
- Option to skip pages without diff

Fixed
- Problems when using the plug-in and comparing uncommitted stuff.

Added
- Support for user defined layer names.

Fixed
- The 'only in XXX' message worked only the first time, after caching the
files it wasn't informed anymore.

Changed
- Now PCB layers are cached by layer ID, not name.
- Lines in ex/include lists that begin with are just ignored.
Before we let them fail to match because the names weren't valid.
This avoids confusing warnings.

Added
- Support for adding/removing SCH sheets

Fixed
- KiCad 5 problems with inner layers (undefined names)

Added
- Support for adding/removing PCB layers
- Option to specify the layers to use, instead of excluded

Changed
- The red/green colors to match text mode diff tools