Remove deprecated OpenGL 1.1 Fixed Function Pipeline Renderer

[Stan]

While still functionnal the Fixed Function Pipeline code is old, OpenGL 1.1.

The main arguments for it are that it is very old (1997!) it is slow, it’s not very well tested, as it’s not possible to enable it through the options (although the hardware detection can force it), and while it works, it will crash if any of the new features are enabled. And the last one is the fact it was marked as deprecated almost 7 years ago: in r13156 The only argument “for” that I can find is that some users (62/10000+) use it.