Some angry bird physics.
this project is for me to test and fix any bugs in the physics program as part of the angry birds collab im participating in. i have managed to fix 1 bug so far known bugs: when landing, there is a chance for the bird to stop responding to mouse clicks. this is due to a glitch that stops the velocity variables from resetting to 0, therefore halting the reset process as the code can't detect the variables as 0. this seems to be triggered by bouncing off a slope directly before landing credit to @yingj for making the base script
