Added functions map() and constrain().
Added functions map() and constrain().

* Need to map avg_position values from Leap Motion to input values for the servos such that the range is linearly scaled and constrained to a safe limit set for each servo separately.
* implementation remains to be tested
* Further work: can add a sensitivity knob to make the scaling sub/super linear
* No bugs to fix yet :)

cvb0rg/LeapMotionRoboticArm,cvb0rg/LeapMotionRoboticArm