Removed unused create function.
Renamed persistence.py module to progress.py
Removed assets folder with icon that is no longer used.
Created ossos.gui.views package.  The old views.py module is in there, 
called app.py.
Split main view module into multiple modules with narrower scope.
Removed method that is no longer used.
Moved error handling dialogs out of ossos.gui.errorhandling into a new
ossos.gui.views.errorhandling module.
Removed unused exception classes in storage.py.
Minor refactoring.
Removed phot_failure parameter from ProcessRealsController's 
on_do_accept method which is no longer needed.
Merge pull request #167 from drusk/cleanup

Cleanup