Changed the comment for the sprite caching optimization to inform the user of a way to beter implement the feature. However, in order to get this done, that's not entirely necessary that we implement it.
Merge pull request #64 from jocelynlih/jocelyn

Issue #45 #46
Just moving a few master art files around to where they should be
Merge branch 'master' of https://github.com/jocelynlih/SwiftGameBook into paul
New artwork for the outside environment. Also, since it looks like touching the box causes you to die (and because you can't run into the box because that would mean walking on the ground, which is death) I changed the box to a box of TNT. The matching asset for the outside environment is a bear trap.
Merge pull request #65 from jocelynlih/paul

New art for outside environment, indoor "box" turned into box of TNT.
Added exit button art
exit sign assets
Merge pull request #66 from jocelynlih/paul

Added exit button art
We can't use the frame for our ground plane. The frame is set to AspectFill, so the frame extends beyond the top/bottom of the screen. I've created a "viewableArea" as part of our GameScene class so we can use that rect to specify scene-frame-relative coordinates within the view space. The ground plane has been adjusted to this.
Merge pull request #68 from jocelynlih/paul

Paul
So we will set for 4 levels :)
Add more power ups to level.