Added PythonLexer for Scintilla, but it appears there is no way to make this work.

Leo build: 20140907093923
Updated to-do list

Leo build: 20140907094222
An important reorg: moved class LeoQtGui to a new file: leo/plugins/qt_gui. All tests pass.
This revealed that there are are *two* modules named qtGui: the actual Qt module and leo/plugins/qtGui.py.
Coming soon: moving all remaining items in leo/plugins/qtGui.py into qt_frame.py.

Leo build: 20140907094521
A few tweaks related to qt_gui.py.  All tests still pass.

Leo build: 20140907095143