Garbage collection, Pymunk consistency

Added

• Code vulnerabilities automatic checks
• Example videos in examples/images/

Changed

• Manny reforms in code style, to make the dynamic part naming conventions consistent with Pymunk.
• Images in the README.md!

Fixed

• You can now define linkages with an enormous number of legs. Systems with many should no longer break physics but your CPU instead :)

Removed

• Many lines of codes and comments that were no longer useful.