Changed the naming conventions used for cell types to better reflect that of iOS controls.

Changes:
	LinkingCell -> Linker
	Photo -> Image
	ListBox -> Picker
	CheckBox -> Switch
	TextEntry -> TextField
	TextField -> TextView

So the complete list of cell types currently created is as follows:
	Linker
	Image
	Picker
	Switch
	TextField
	TextView
	Button
Implemented cellState manipulation for the TextField and TextView cells.
Reorganized some code, minor optimizations.
Ready to merge into master branch.