Updates to ideas page in advance of GSoC 2013 application.

* Remove Lemke-Howson project completed by Tobenna in 2012.
* Add project to complete integration of Action Graph Games library
* Add project to refactor game representation library
Add EEE algorithm to ideas page, link to GTE wiki in index of docs.
Remove duplicated Python test code.
Implement file associations for OS X.

This updates the bundle metadata for OS X to associate the graphical
interface with the .gbt, .efg, and .nfg file types.  Relatedly,
this implements the wxApp::MacOpenFile() hook required to handle
opening files directly from the Finder.