Added a KinematicsTester unit test system. So far, I have only added tests
for solveForAcceleration(), which the program passes so far. Future plans
include finishing the rest of the unit tests for the solve functions, finish
making the solve functions, and then begin the kinematics widget.

Also added the function updateVariables(Kinematics::VARIABLES, double value)
which can be publicly accessed to change the calculator's variable structs.