* Document & comment code
* document functions & add pages for groups
* Run clang-format
* Fix most review change requests
* Fix typos, add information on using multiple Opera Cake boards
* Update documentation
* Changes requested by @Straithe
- update project brief
- set paper type to letter
- move doxyfile
* Changes requested by @martinling
Excluding the USB API versioning
* Remove incomplete USB version info
The required versions were only noted at a few places. Will add complete info later, but for now, it's removed
