Document apps

[theFork]

• [ ] Complete application pages (expression.dox, switcher.dox, ...)
  • Add some nice pictures
  • Provide more detailed descriptions
  • Document GPIO pin mappings
  • Add links to hardware repos (https://github.com/haggl/uMIDI-hmi, https://github.com/theFork/uMIDI-wah, https://github.com/theFork/uMIDI-switcher)
  • [ ] Expression
  • [ ] Switcher
  • [ ] Wah
  • [ ] Whammy
• [x] Elaborate hardware section
  • [x] Add board.jpg
  • [x] Maybe move the contents of pin_map.md to Doxygen as well?
• [x] Update README (#41)

[ghost]

Github pages ftw: https://thefork.github.io/uMIDI/

Created with this awesome tutorial.