Creating branch for particles.
adding particle effect for when the ball bounces on something that it has contact with. makes it look like an explosion happens when a ball hits a brick in breakout, but also does the explosion for paddles.
Basic interface for creating and modifying collision groups.
Adding groups image in menu tableview.
Added support for grouping in project creation and sprite creation.
Merge remote-tracking branch 'origin/sprite-grouping' into sprite-grouping
Remove toolbar from selected group table view.
Add animation for when grouping view goes back to canvas.
made it so that explosion only happens for the bricks for alpha. still need to make this generic and reusable.
Merge branch 'particle-physics' into sprite-grouping
Fixed project bug.