One-time force effects from external sources (Patreon)

I'm just in the final stages of testing this before pushing. It allows you to easily apply forces to the controller (from explosions, swords, bouncers, etc). The force slowly decays after impact for a smoother repellent. 

You can also choose to make it additive or replace the current external force as well as reset the player movement before the force is applies for a more reliable reaction.

Let me know if there's anything else I should implement before pushing~