Adding TableLayout as a submodule

See https://github.com/EsotericSoftware/tablelayout
Reorganizing support classes so they can be used by the tool
Fixed dhcoder.libgdx tests
New tools.scene and dhcoder.libgdx.tool modules
The beginnings of an undo/redo history class.
Caught more test cases
Minor optimization, reusing an UndoGroup instead of creating a new copy
New test for nested records
Renamed Undo<T> to UndoPtr<T>
Keyboard commands
Removed annoying inspection
Fixed bug in ArrayMap getValues
Added fuzzy searching for commands
Removed redundant extention
Updated readmes
Removed thirdparty folder
Scene Tool proof of concept works