As glGen*() only reserves object name without creating it, it must be
ensured that the object is created before calling functions which expect
already created object (such as glObjectLabel() or glBindTextures()).
Allows me to remove quite a lot hacks in the tests.
With ARB_multi_bind it is needed to associate the texture with some
target before calling glBindTextures(), otherwise the texture is
treated as invalid.
The only places where they aren't absolute are:
- when header is included from corresponding source file
- when including headers which are not part of final installation (e.g.
test-specific configuration, headers from Implementation/)
Everything what was in src/ is now in src/Corrade, everything from
src/Plugins is now in src/MagnumPlugins, everything from external/ is in
src/MagnumExternal. Added new CMakeLists.txt file and updated the other
ones for the moves, no other change was made. If MAGNUM_BUILD_DEPRECATED
is set, everything compiles and installs like previously except for the
plugins, which are now in MagnumPlugins and not in Magnum/Plugins.