add OpenGL 3 port

[mgood7123]

fully ported to OpenGL 3 context

[behdad]

Thanks! I like the code to still build with GL2 as well. Any chance you can work on that?

[mgood7123]

Thanks! I like the code to still build with GL2 as well. Any chance you can work on that?

i will try when i find the time

i am not sure how to detect the available GL version at runtime, eg if the GPU supports GL 3 or GL 2

[mgood7123]

how about this? :)

now it has demo-gl2 and demo-gl3 :)