Merge pull request #9 from deathcap/master

Add fall distance calculation
clean up some hidden class stuff
0.1.0
bugfix: check two frames prior, not one frame prior
0.1.1
fix for old_resting_y. thanks @deathcap!
0.1.2
Fix old_resting_y variable reference
Merge pull request #10 from deathcap/fallfix

Fix fall distance calculation
0.1.3