- Added SPI for JCas classes
- Added test that FSClassRegistry is able to load JCas classes through the SPI
- Push exclusion of META-INF down into the bundle modules because we do not want to exclude the META-INF/services for SPI testing

- When loading a class through an SPI, use its classloader for the generator lookup
- Add own type classes for SPI testing to avoid interfering with existing tests

- Update template

- Exclude SPI control file from rat check

- Added a bit of documentation