initial extruded extent
option to hide top and bottom
separate functions
calculate bounding sphere
relocated functions, added tests
modified parameters
added a few more tests
perimeter calculation WIP
detach walls
texture coordinates
texture coordinates with rotation
cleanup
Merge branch 'batching' into extrudeExtent

Conflicts:
	Apps/CesiumViewer/CesiumViewer.js
	Source/Core/ExtentGeometry.js
updated tests
Merge branch 'batching' into extrudeExtent

Conflicts:
	Apps/CesiumViewer/CesiumViewer.js
consolidate duplicate code for extruded and non-extruded extents
Merge branch 'batching' into extrudeExtent
Merge branch 'batching' into extrudeExtent
updated documentation
refactor