Only nodes under units will be not Buildable now; however, there is a bug that sometimes makes the wrong nodes not Buildable. No information on how to reproduce bug yet.
Added part of translated PathFinder: Grid, Node, MapNode(SquareNode), Edge, NodeComparator, and KNodeComparator.
Merge branch 'master' of https://github.com/rhuang1/ptown-chance

Conflicts:
	ProjectQuartz/Assembly-CSharp.pidb
	ProjectQuartz/Assets/ProjectQuartz.unity
	ProjectQuartz/Library/ScriptAssemblies/Assembly-CSharp.dll
	ProjectQuartz/Library/ScriptAssemblies/Assembly-CSharp.dll.mdb
	ProjectQuartz/Library/assetDatabase3
	ProjectQuartz/Library/expandedItems
	ProjectQuartz/Library/guidmapper
	ProjectQuartz/Library/metadata/82/825b9061e3eb3864aba478ff43e84ad6
	ProjectQuartz/Library/metadata/9e/9e37c3c6bdb5b5e4689a02ae70cf4d88
	ProjectQuartz/Library/metadata/eb/eb0349e22d1a1fa47b3d51454801e5a5
	ProjectQuartz/ProjectQuartz.userprefs