Merge pull request #1 from jpumpelly/master

adding movement
setup directional walk animations
rearranging convertToEasyStarGrid method to live in the XRoads.Grid namespace where it makes more sense
refactoring findDirection method in creep.js
added findDirection as a prototype method on the creep class for more efficient re-use
created CreepManager to manage creeps
added type support for creeps
forgot to include creepManager.js
Added gridNodes.js data model. Began trying to implement the nodes into creep movement. got stuck.