check for overflow vertex indices, fixes issue 6135

thx @ JMC47 for identifying the reversion, creating a useful bug report with fifo log :-)
Had this sitting around for a while to fix nogui.
Switch to using bitfields in the streambuffer class so we can exclude buggy streambuffer types. This disables pinned memory on ATI for GL_ELEMENT_ARRAY_BUFFER because it seems to be buggy. This fixes ATI for me.
Prefer D3D11 and OpenGL over D3D9 by default.
Mark the Direct3D9 backend deprecated.
Fix description of disable fog, and move it to enhancements tab.