OpenTK versions of examples

This is my version of the examples ported to OpenTK. @zsbzsb and I have worked through a lot of changes since my initial commits, but it should be ready now. I have tested them on Windows and both examples are working.

Updated .csproj files that use OpenTK instead of Tao as a dependency are also included. However, I haven't been able to test these in VS2008 (I don't have a copy of it), but they should work as well (the references were all that was changed, and VS2012 is able to import them correctly).

Also included are more recent builds of the extlib files. I can revert these to the currently bundled version if necessary.