removed .bak files
Revert "removed .bak files"

This reverts commit 6e3b26554bc6db9df4b4b4dc3afca4b1fb0e309b.
Merge branch 'master' of https://github.com/djragsdale/hackathon
added gravity and collision detection
updated user authentication and help section
Fixed gravity method, now exponential
Merge branch 'Hester-v2' of https://github.com/djragsdale/hackathon into Hester-v2
Merge branch 'Scott3'