Implemented interruptless processing and some bugfixes

- Fixed bug that scetch could not be compiled (using VisualMicro)
because Wire.h was not found. Arduino-Libraries must be also included at
top of the *.ino file to prevent this problem.
- Fixed bug that first interrupt was ignored
- Added option LOWLEVELCONFIG_GYRO_USE_INTERRUPT. If set to false, the
interrupt signal is ignored. Data is processed if the FIFO buffer has
enough bytes and the interrupt status is set to "data ready". If set to
true, also the interrupt signal itself must be received to enter the
processing method.
- Minor modifications in Quaternion class and config.h, debugging is now
enabled/disabled using the flag LOWLEVELCONFIG_ENABLE_DEBUGGING (set to
true or false).
Implemented YawPitchRoll
Added debugging with NeoPixel, tested some reset code, not working yet
sbus debug, yaw test

Defined some debug output for sbus, using neopixels to show current yaw
and target yaw
Improved SBUS parser, implemented basic ESC output

- The parser for the SBUS protocoll has been improved, it is now able to
resync on the start byte even if there is another byte in the data
stream which has the same value, but actually is a data byte

- Implemented a basic ESC throttle output calculation. For now, it has
no gyro feedback loop or PID governor, it simply uses the
throttle/pitch/roll/yaw input (RC / sbus input).
This is just for testing, however, if all 4 motors and ESCs are
identically calibrated and we tune some parameters, it should be
possible to control the quadrocopter like a  non-stabilized helicopter.