This adds support for rendering models using thick lines (that means
lines wider than 1 pixel) which is required by the hardpoint HUD gauge.
This feature was present before the switch to OpenGL code and had to be
removed since the core profile does not support rendering lines wider
than 1 pixel.
This uses a geometry shader for converting all the triangles from a
model to 3 quads along the triangle lines which are as thick as set by
the model renderer. Geometry shaders are quite slow if they generate a
lot of geometry (and this generates 4 times the usual amount of geometry
in the shader) so it's probably not a very fast rendering operation but
it is only needed once per frame so it shouldn't be too bad.
I also added support for the RenderDoc API since I needed that for
debugging and it might be useful in the future. It will only become
active if RenderDoc is actually attached to the process so in most cases
the new code will do nothing.
