stuff
some more keys
collision stuff

-cleaned, commented and optimized collision code
-switched traces with ST_Logger.logs
fixes, comments and cleanup

-fixed interpolator stuff so that it uses detachments instead of just
sprites
-fixed deltatime offset on st_interpolator
-renamed float interpolator to "oscillator" since that's what it does
trying to fix a problem with deltatime stuff
more fixes

because we have a variable timestep now, we can't actually use deltatime
directly. Instead, we have to use STI.corrector when we want to do
integration since it's a combination of deltatime and the timestep.
figured out a basic replacement for the pathing thing
easing functions
merged seans branch