Cleanup of GeometryUtils and associated tester programs
* split off SchemaGdxConverter (engine) from GeometryUtils (editor-only)
* added ShapeEditor as stand-alone test (split from TexturedShapeEditor)
* updated GeoTester to use offsets, draw strings when required
Added perspective-corrected path-finding for polygons
* PathUtils contains general utilities (eg.: projection matrix manipulation)
* PathFinder finds the paths, allows path-segment iteration
* PathFinderTest contains JUnit tests for above
* PathTester contains a graphical test
Engine integration for path-finding
 * Path transformed by PathProcessor into PathComponent: poly+perspective
 * Goto effect executed by GoToExecutor adds WalkComponent: actual walking
 * PathSystem updates positions of elements with active WalkComponents
 * Integrated into cooldemo: click on alien to walk him around
Merge pull request #371 from manuel-freire/element-paths

Element paths