[OpenTK] Make VB.Net overload resolution happy

GLHelper.cs contains a number of overloads that cannot be resolved by
VB.Net. We cannot remove them, as that will break
backward-compatibility, but we can hide them by moving them after the
autogenerated overloads in GL.cs.

Terrible hack, but it appears to work.

Issue originally reported at http://www.opentk.com/node/3554 as "OpenTK
1.1, VB.net and ambiguous functions."
[Win] Do not raise KeyPress for control chars

This matches the documented behavior of the GameWindow.KeyPress event.
[Doc] Updated documentation for release
[Doc] Removed pdf OpenGL/AL specifications in favor of html links

This reduces download size significantly without loss in functionality.
[Doc] Fixed doxygen latex-to-pdf conversion

pdflatex will fail when a <seealso> elements is placed within a
<summary> element. This is now fixed.
[Doc] Removed deprecated doxygen directives
[Doc] Updated version number in doxygen documentation
[Doc] Add links to OpenTK manual and API reference
[Doc] Generate oxygen reference for OpenGL/AL

This is useful, even though it takes a lot of time and generates large
files.
Added stable release notes and nuget package links
Fixed line breaks in release notes
Fixed line breaks in release notes again

links require extra new lines
Add ErrorHelper to bindings.

In DEBUG builds wrap ErrorHelper around native calls.
Use managed method name.
OpenGL ErrorHelper in DEBUG.

Very hardcoded, but working ErrorHelper for OpenGL namespace.
Remove Console.Writeline statement.
Begin/End turn off/on error checking.