Started Sprite Model

-Added SpriteModel class
-Renamed QML registered type PetModel
-Updated DB for inserting SpriteModels
Need to add a QDeclarativeListProperty for SpriteModel
Added a QDeclarativeListProperty for Sprites

-QML can now re-add previously created objects on screen

TODO: set limit to the number of objects that can be created
TODO: clean up sprite creation functions
Added desert world
Created Splash Screen before starting game
Added Sprite Creation Limit + Comments
Merge branch 'spriteModel'
Merge branch 'newworlds'
Merge branch 'splashscreen'

Conflicts:
	qml/petn9/FirstRunChooseName.qml
	qml/petn9/Game.qml
	qml/petn9/main.qml
	qml/petn9/pets/AbstractPet.qml