All other HAL functions have status as the last parameter, only PDP did not.
This changes makes the PDP parameter order consistent with the rest of the HAL.
Change-Id: I725e33f75deab34e6a83b7048b2d6c365fa56a21
Implemented setTaskPriority() and getTaskPriority() in Task HAL API
Removed all other unimplemented functions in HAL and removed spawnTask()
Replaced instances of pthread_t* with TASK typedef
Removed unused HAL error constants and removed commented-out classes and functions in wpilibj's HALLibrary
Changed Task class API to match the construction semantics of a std::thread
Change-Id: I3bc951a3da90d24c5589fae4d1ca2bb60225c873
