Made stopping sound depend on falling (to prevent false positives)

I made the stopping sound depend on the fact that the device was previously falling. I set 'falling' to YES when the device was falling and set a 2 second timer to set falling back to NO, and I made the stopping sound require 'falling' to be YES. This way, if you pick up or throw up your phone, it won't set off the "hit the floor" sound.

Hope you like it!