merge with branch

merge with VNB60 branch for commisioning of controller
added SpeedControl Example

added SpeedControl example as additional sketch. Bugfixes of speed
calculation and BEMF voltage measurement.
add BEMF measurement
replace periodical Timer trigger by ADC trigger for Interrupt

sketch: - added handlind of command via serial link
lib: - control loop ISR is triggered by ADC not timer anymore
- added DC link voltage measurement
- defines dependent on board revision
- added start/stop functions
update from swenii fast ADC