Add Dependencies for signals

The parent class is nessecary for signals to be defined. A single
signal, user_stories_update, is defined for the class.
Register slot for user story update

Register the update backlog function to be called when a signal is
emitted from the controller notifying that the backlog has changed.
Emit user_stories Signal for Add Story Call

The controller emits a singal letting all observers of the signal that
the data has been updated.
Fixed Poor Spelling

Geez, @benjic learn to spell
Create Stringer Mixin

The stringer class allows any class to create string based identifiers
based on a common pattern
Make UserStory Stinger-ed

UserStories now use a string based id. The mapper uses the underlying
_id property to map integer based ids within the database.
Implement Models as IdStringers

All models generate string based id's.
Map Numeric Ids to Columns in Persistance

When models are persisted to the SQLite backend the ids are stored as
numerics.
Removed Debugging from UI

Reverted button names to orignal values now that the backlog populates
automatically and user story additions are functional.
Merge pull request #29 from benjic/signal_slot

Signal/Slot Events