Moved sensors and other devices to platform.devices sub-package
Implemented Fifo modes for ADXL345
NullSensorSource now returns 0
ATMega1284p: Added missing external interrupts INT0..2
devices/Button: Button implementation fix

* Now return value is updated
* isActiveLow parameter is respected
Merge pull request #2 from ejoerns/pull-req/button-fix

Fix INGA Button simulation
[inga] Correct LEDs for INGA platfrom

The INGA platform has exactly two controller-driven LEDs:
A green one and an orange one.