Use the generic device::SPI locking strategy.
Hotfix: Bumping up interrupt stack size, which fixes a number of evil symptoms seen in some test cases. Needs more inspection, but this fix holds for the test cases
Hotfix: Increase work stack sizes
Hotfix: Improve UART1 receive performance
Disable USART1 DMA Rx on FMUv1
Implement Spektrum DSM pairing in V2

- Bind control for V2
- Relays and accessory power not supported on V2 hardware
DSM pairing cleanup in px4io.cpp

- Simplify parameter range checking in dsm_bind_ioctl
- Replace DSM magic numbers with symbolic constants
px4io test and fmu test now work over USB as well
Allow px4io detect to be run when IO is already running
Make mixer upload not depending on single serial transfer error
Look for the appropriate images in the uploader
An even number of bytes is when modulo 2 is zero, not modulo 1 is one.
Fix binding states for DSM
Refactor dsm binding code in px4io.cpp

- Move repeated code into member function
Implement message based receiver pairing
rgbled: major cleanup and bugfixes
rgbled: more cleanup
rgbled: copyright updated
Fix backwards ifdef in dsm.c
Finally get the #if right!!!