Added some sequence Diagrams

AS ABOVE
Modified Design based on Thursdays Tutorial
Added 3 Sequence Diagrams:
	- ConnectScene
	- LinkItem
	- SaveScene
Added Use Case Diagram (version 1)
Modified existing Sequence Diagrams to reflect design changes.

- James C.
Design changes

Changed Design to reflect new ideas presented during Thursday's
Tutorial.
Added 3 Sequence Diagrams:
- SaveScene
- ConnectScene
- LinkItem
Added Use Case Diagram
Modified existing Sequence Diagrams to reflect Design changes.
Added Sequence Diagrams and Updated Class

Sequences Added:
- Add Scene
- Add Item
- Remove Item

Also altered functions in AddItemWindow Class:
- setDescription(String)
- setName(String)