blah commit, just need this outta the way
avr-usbraven: lufa loop in contiki WORKING
avr-ravenusb: use input values from rime broadcast
avr-ravenusb: adjust logical value limits
integrate everything for out of the box build

big commit:

- add submodules: lufa, one contiki for inga build, and another contiki
  for avr-raven build, with some patches
- adjust makefiles to work with libs from submodules
- update .gitignore
avr-ravenusb: new descriptor strings