modified format of level files(changed case)
Added Model for Level Builder
Merge branch 'master' of https://github.com/tmzhuang/pvz-reloaded

# By arzaanirani (7) and others
# Via Christopher Nguyen (2) and others
* 'master' of https://github.com/tmzhuang/pvz-reloaded:
  Fixed Errors in the test case. Complies and works fine!
  Added in Undo/Redo  SequenceDiagrams.
  Update ZombieFactoryTest.java
  Create WallnutPlantTest.java
  Update PlantTest.java
  Update PerishableUnitTest.java
  Create FlagZombieTest.java
  Create DefensivePlantTest.java
  Create ConeZombieTest.java
  cleanup
  Misc clean up
  added tests for real time and comments
  Updating gitignore
  Force adding GameModelTest
  added pause and resume as well as an option to play real time or not, there is currently a bug where the buttons gui are not being refreshed properly
  uncomment some lines as code as the realtime is not causing the bug
  added realtime but there is a bug with undo and redo