Simple Toothed Belt Implementation

Description: This submission contains a toothed belt drive implementation. Is a simple combination of the "wheel & axle block" combined with spring and damper to simulate the flexibility of the belt. The physical effects on the teeth (like deformations) are not considered, as well as there is no check if the belt goes slacking. The file "testing_torsional_stiffness.slx" is a representation of a toothed belt drive which has a pulley blocked and another one attached to a torque source. Run the model to see how the moving pulley can pull and stretch the belt until it stops at a certain angle, when the torque is not enough to further stretching the system. No slippage occurs at the teeth.