Merge pull request #101 from valeriog-crytek/master

GL fixes and Python improvements
Re-do text rendering to use stb_truetype so it's portable to linux
Handle mismatched swapchain & window sizes

* The debug text used to render at swapchain dimensions, but that could
  make it unreadable if the window was significantly different, so apply a
  scaling factor to account for it.
Better handling of NaN/inf in range histogram

* This is the proper fix for 87bcde1c which is also more explicit about
  what is going wrong. Thanks to the anonymous user who mentioned that they
  clicked auto-fit before hitting the range histogram crash, which got me
  on the right path to track down the exception!
Update README.md clarifying current API support
add source code pro to license & credits files
Have captures listed on overlay decay after 20 seconds
Added visualization of rasterizer state for OpenGL.
Add visualization of most missing OpenGL texture types (cube maps, texture arrays, stencil, 1D/3D textures, integer textures), take selected mip level into account and point sampling when required.