Improves error messages on ice/ice-qt.py
Refactors Configuration into a much more useful object

Currently Configuration just acts as a gateway to the like 3 values that are stored in config.txt. Now, configuration is in charge of all data that goes through persistence. This means config.txt, consoles.txt, and emulators.txt.
Moves class methods of BackedObject into BackedObjectManager

BackedObjectManager will be in charge of things relating to the groups of consoles/emulators together.