Add biscSendInt() method and correct biscSpin methods

To simplify sending integers to the Create, I added a helper method that will handle splitting the int into high and low bytes.

Additionally, I corrected the biscSpin methods.  These should not need to take a radius as a parameter.  Instead, the radius should be the special value BISC_SPIN_CW or BISC_SPIN_CCW.  The velocity should determine the spin direction, so we should just use BISC_SPIN_CW and allow a negative velocity to cause it to spin CCW.