add mpu60X0 driver
onboard sensor thread
init error level counters
MPU6000 reset before initializing
MPU6000 fix sensitivity
spi config, start sensor thread
add onboardsensors.c to sources
add gyro command
spi cs fix
heartbeat & error led in same task
fix SPI CS init
tools.mk add reset command
add .tags_sorted_by_file to gitignore
rename error level functions, add safemode, change LED behaviour
fix spi-cs wait, increase spi clock speed for sensor registers
Merge branch 'mpu6000'

- mpu6000 driver added
- onboard-sensors thread that reads the sensors
- better LED behaviour
- safemode api
- changed error api