Added a cat as an obstacle for the mouse in Maze. Simply replaced one of the random tiles with a cat.
Removed the additional tiles_mouse_2.png
Revert "Removed the additional tiles_mouse_2.png"

This reverts commit d2d3db631ed6dc58e815b7bc9cd2a2826688e76d.
Revert "Revert "Removed the additional tiles_mouse_2.png""

This reverts commit 587222f52cf8d1f21f200193ab821ae3323ad679.
Reverting the mouse changes.
Revert "Added a cat as an obstacle for the mouse in Maze. Simply replaced one of the random tiles with a cat."

This reverts commit 8178ff4535bc74024a6a57a5d802fbe3cea2ca6b.
Added the obstacles in mouse and cheese. The obstacle still shows there is a path, but when you tend to walk on it, it shows as if you hit a wall.
Corrected the description for normalize function in Karel.
Removed the redundant code in rending the maze (normalize).
Merge pull request #30 from nanan9177/mooc

Added obstacles for mouse and cheese in Maze
Merge pull request #33 from brokenairplane/mooc

Removed obsolete function displayInterstitialOrCloseModalDialog from common.js and maze/turtle templates.
Convert levels form structure of arrays to array of strucures.
Merge pull request #34 from brokenairplane/mooc

Updating generateXMLForBlocks in common.js to be more readable.
Merge pull request #41 from brandonbloom/soa2aos

Convert levels form structure of arrays to array of strucures.
Removed TODOs from template and cleaned up the text. More to do after Ellen's CL that moves common messages. Pushing this to avoid merge conflicts, and have maze/template.soy better prepared for final changes.