Big FOC fix

• Fixed anti-windup issue, this could cause very strong unwanted regen in the upper speed range - SAFETY CRITICAL!
• Improved idc filtering for smoother DC current limiting
• add a parameter 'sincosofs' - this is the midpoint reading of a sin/cos encoder output, removing the requirement for a precise 1.65V midpoint and resistor divider if using, for example, a sin/cos chip that doesn't work on 3.3V VCC (MLX91204 requires 5V)
• Obey DC voltage limit in boost mode
• Disallowed saving parameters in run mode
• Added support for BMW i3 gate driver board SPI ADC
• Changed ADC sample time to 7.5 clocks
• Taking 8 samples from last PWM period instead of 3
• Rotor movement compensation becomes active above 10 Hz
• Auto-detect flash size and write parameters to according address