This stops the virtual method call from within the Renderer constructor.
The initialization here for GL had to be moved to VideoBackend, as the
Renderer constructor will not have been executed before the value is
required.
Making changes to ConfigManager.h has always been a pain, because
it means rebuilding half of Dolphin, since a lot of files depend on
and include this header.
However, it turns out some includes are unnecessary. This commit
removes ConfigManager includes from files which don't contain
SConfig or GPUDeterminismMode or GPU_DETERMINISM (which means the
ConfigManager include is not used).
(I've also had to get rid of some indirect includes.)
It's not available in OpenGL ES and officially it's not supported on OpenGL 3.0/3.1.
Fallback to old depth range code if there is no method to disable depth clipping.
It's more important to have correct clipping than to have accurate depth values.
Inaccurate depth values can be fixed by slow depth.
Sorts out references that cause some modules to be kept around after
backend shutdown.
Should also solve the issue with errors being thrown due to the config
being loaded after device creation, leading to the incorrect device being
used in a multi-adapter system.
