Aviatrix3D Changes

Changes since 2.0 Beta 1

- Reorganised the interfaces to the rendering pipeline to not use 
  most of the user-facing classes. Now uses the separate Cullable/
  Renderable-derived interfaces. Some small exceptions still
  remaining but will be cleared by the next beta release

- Addition of SWT lightweight rendering capabilities (Draw2D and GEF)

- yUp handling on textures was back to front

- Introduction of VBO capabilities

- Make system now builds Eclipse plugins directly rather than needing to
  hand-roll your own.

- Several package changes to be more consistent. Most beta 1 code will
  not compile without these package changes.

- A simplified Billboard node (not quite complete) and LODGroup node in
  the extensions area that will automatically apply this behaviour every
  frame that they are visible.

- Added a debugging pipeline set of stages to help end users debug strange
  behaviour either in AV3D or their own code.

- Partial fix of the texture/shader object deletion code when they get changed

TBD:

The Pipeline/RenderingManager setup will change with the introduction of 
a new Window class. This will allow the system to have multiple separate
windows looking onto a shared scene graph. 

Complete the rest of the pipeline cleanup to remove references to 
SceneGraphObject.

Complete the audio pipeline implementation

Find that dratted Culling bug that sometimes appears when an object is
under a series of transforms with rotations.