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).