Added -lc to Makefile linking to get rid of multiply defined functions
when adding code that compares float to zero.

Got MotorSetTorque working.

Added s_ftos(float) to produce a string that mimics %.3f, because
the %f printf format does not work.

Added ktypes.h, which includes <inttypes.h> to define types like
uint16_t, and also defines bool type.