Remove fallback when EXT_texture_filter_anisotropic isn't supported
Removal of gfm.opengl.textureunit.TextureUnits which was now useless.
Fix examples.
No more loss of generality in context creation.
Remove boring one-size-fits-all logging.
Less boring one-size-fits-all logging.
gfm:freeimage does not depend on logger anymore, since no logging callback.