Merge pull request #87 from jocelynlih/ankur-refactor

Following proper design patterns and demonstrating use of protocols
Fixed a few bugs in the rendering code, made a few graphical updates to art, started a second outdoor level (but stopped).
Merge branch 'master' of https://github.com/jocelynlih/SwiftGameBook into paul
Merge pull request #88 from jocelynlih/paul

Paul
Fixed the endGame() crash bug. Yay.
Merge pull request #89 from jocelynlih/paul

Fixed the endGame() crash bug. Yay.
Merging