First implementation of text but still glyph-by-glyph rendering
Improved implementation by using a texture atlas
More improvements + Ready for JS implementation
- added LoadSystemFont
- moved stuff from RCImp to RC
- added kerning
Implemented text stuff in JS
- TextMeshes for Prerendering of Text
- Using our default render methods now
- Changed some shorts to ushorts
Implemented the same in Imp.WebGL.
Most recent JSIL with font support
First GUI Element: Button
- moved text and gui to their own files
- color is now permanent on a mesh
- added function to convert float4 into ABGR
Button is now ready to use
- Button has its own class
- Input now has an public EventListener
- Button now has an EventListener
- new GUIElement class
Three more event listeners: Up, Enter, Leave
Changed class structure
- moved some fields to GUIElement
- made GUIElement abstract
- TextColor and ButtonColor can be changed
Added border + Refresh method
Merge branch 'develop' into feat_text_gui

Conflicts:
	src/Engine/Core/MoreShaders.cs
	src/Engine/Core/RenderContext.cs
	src/Engine/Imp/OpenTK/RenderContextImp.cs
Renamed shader, updated JSIL
Added second button, changed sender type
Button works now in web
New class GUIText replaces Text.cs
Merge branch 'develop' into feat_text_gui

Conflicts:
	src/Engine/Core/RenderContext.cs
Used RenderStates for GUI rendering
Web is broken, first fixes