Changes for multi-rate PWM output; default and alternate rates. ioctl protocol, PX4IO support.
Convert HIL and FMU drivers to the new multirate PWM interface.
Move PWM rate configuration, etc. into a separate utility and out of the individual drivers.
Make communication rate between IO and FMU configurable
Fixed typo
IO board now disarms when FMU reboots when manual override is not an option
Merge pull request #224 from PX4/pwm-multirate

Pwm multirate