Minimal updates (just the include guards) so Git is hopefully able to
detect the rename and track the history properly.
Everything except Magnum::GL doesn't compile now.
There will be numerous additions to this one so it made sense to make it
a static library instead of a header-only library. That also allows
CMake users to just link to Magnum::OpenGLTester instead of going
through the pain of a huge branching in order to find a correct
windowless application just to run their tests. It could have been done
even without the static library using a INTERFACE target, but that
wouldn't work on CMake < 3.0 (which, unfortunately, quite a few people
are still stuck with).
Unfortunately it's already heavily used elsewhere so I had to go through
the pain of deprecating the old implementation. The old implementation
was header-only so it can't be just typedef'd to the new one as there
would be linker failures. So the old header is just kept as it was, with
only the macros reduced.
103% of use cases use the returned value directly without checking, so
we might as well do the check ourselves. Added new function hasCurrent()
and added deprecated backward-compatibility conversion and -> operators.
Wow, that creeped to a lot of places.
Last dinosaur from the pointer age.
Mesa drivers (rightfuly) complained that S3TC is not supported on 3D
textures, the packing had weird behavior on NVidia but it passed w/o
problems on AMD. Now should be okay on all three, yay!