Test to see GL 4.5 possibilities

[karelholubicka]

Hi Alex, if you read this so I finally managed to create PR.

I tested and downloaded my master separately and it compiled even on another machine,
so hopefully all new dependencies will work.

I am trying to develop Virtual studio.
Original idea was to use VR controllers as cameracontrollers,
for each of two VR controllers use two windows as foreground+background renderpair,
and send them via 4 NDI streams capable of alpha channel
to vMix videomixer and mix them with live camera images.

I managed this to work,
but NDI timing problems ruined this scenario.
Both NDI and vMix did not gave me enough control over timing,
so final image was not reliably time-stable.

Next solution was to handle mixing internally,
but this required BlackmagicDesign IN+OUT

• shaders on GPU to perform color keying.
  Developing shaders showed, that
  on my AMD hardware (and Intel too)
  compatibility mode simply did not work with core commands.
  This lead me to use more contexts, one compatible and one core
  and developing separate GL4.5 features.

Therefore:
New code, especially renderer, contains huge amount of crap
only for virtual studio purpose,
including ad-hoc test and so.
I added fixed "useIO" constant which switches off all IO needed for studio

MaterialMapperModernGL, RenderMesh and SceneRendererModernGL are probably only places
which may be usable for your Viewer upgrade.
Based on this:
http://dreamstatecoding.blogspot.com/2017/01/opengl-4-with-opentk-in-c-part-1.html

You mentioned in comments:

• Matrix are somehow transposed.
  Yes, probably all of them.
  As AB = BTransposedATransposed,
  you probably transposed one on the beginning,
  an all rest of the code has
  1/ matrixes transposed
  2/ multiplying order of matrixes switched

What i am looking for is to update Assimp to latest version,
I see it is now over 4.1, while assimp.net stayed at 3.1.1.

You will see,if this update is worth anything :-)
Anyway, thank you for your work. Without your well structured codebase my project would be probably impossible.
Cheers,
Karel