Add support for a hardware bind plug (PB5 pin 41) and alternative

default settings for AlienWii32 (8 brushed ESC) based on the NAZE
target.
I'm with treym on this stuff - #ifndef is ugly, and magic numbers are ugly. add #defines for DEFAULT_XXX_YYY for the stuff you wanna change, and propagate them in all platform-specific #ifdefs in board.h