Fix compile warnings in Examples.

This commit fixes every current warning in the Example code bar two.
Both due to the use of the OpenTK.GameWindow.Joysticks.
Fix compile warnings in Converter.
Fix XML documentation.
Disable Obsolete warning.

IGraphicsContext.VSync property is obsolete, but we have to call it in
the GraphicsContext.VSync implementation, so disable the obsolete
warning for this one use.
ModalLoopCallback is never assigned.

ModalLoopCallback is never assigned, so always has it's default value
null. Replace all uses of ModalLoopCallback with null.
Remove unused fields and variables.
[GameWindow] Do not override Target*Frequency in GameWindow.Run()

This patch makes the following code work as expected:
```csharp
var gw = new GameWindow();
gw.TargetRenderFrequency = 60;
gw.Run();
```
Fixes issue #69
Add string ComputeSize to Parameter.
Store count attribue in ComputeSize.

Also remove the COMPSIZE() text if present.
Add length helper text to params.

If a param has ComputeSize text add [length: {0}] helper text to the documentation.
Merge remote-tracking branch 'frassle/warnings' into develop
Merge branch 'issue69' into develop
Fixed NRE when calling Toolkit.Dispose() more than once.
Updated OpenGL definitions
Fix discrepancies between mono and .net
[Graphics] Improve compatibility with Feb2014 release (WIP)
[Bind] Added overloads for backwards compatibility
[Bind] Clean up BindStreamWriter implementation

Instead of inheriting and overriding StreamWriter methods, it now
forwards its parameters to an internal StreamWriter, after applying the
necessary formatting changes.

This shields us from the StreamWriter implementation differences
between .Net and Mono.
[Graphics] Synced with Khronos repository

Adds:
- INTEL_performance_query extension
- “count” attribute fixes for multiple functions
Merge remote-tracking branch 'frassle/compsize' into develop