Added 2 built-in functions to the motor controller that could be useful debugging the hardware, sleepUntil and led. The led function can be used as a simple test to see if the interpreter is working (say by flashing the led once for each statement of interpreted code).
Note that adding these 2 entries caused the entries below them (but higher in precedence) in valve.y to increase their value by 2. This had the unwanted side effect of causing log.txt, parse.txt and tree.txt to change, although only operator values changed. Most of the files here are automatically generated so adding intrinsic functions is done by modifying: valve.l, valve.y, compilerHelper.h and interpret.cpp/.h