Easing Functions:
https://gist.github.com/cjddmut/d789b9eb78216998e95c
Did a bit of code cleanup (made better use of events) and fixed a jittering problem when strafing thanks to this article: http://nothkedev.blogspot.com/2017/11/how-to-cope-with-standard-unity-fps.html
(actually the gif is pretty jittery, but in unity the motion is fluid)
I think flying around looks & feels nicer than running and jumping
(but introduced new problems when walking on moving elevator)
(also not blocking projectiles)
