Major additions. Add more format support, interactive editing, more tests
Add keyboard 2D grid navigation, simplify gridstate representation, plus more minor changes
Change project structure, add keyboard controls for 3D rectangular grids, start writing XML and WebGL exporters, minor refactoring elsewhere
Add more loading and saving tests, begin undo/redo code for grids, start adding xml/webgl exporters,  plus lots of minor refactoring and bugfixes
Continue implementing grid undo/redo commands, start canvas exporter, other minor changes