ALCH-187 - Remove the broken texture atlas code

indra/llrender/llgltexture.cpp

indra/llrender/llgltexture.h

indra/llrender/llimagegl.cpp

indra/llrender/llimagegl.h

indra/newview/CMakeLists.txt

indra/newview/lldrawpoolbump.cpp

indra/newview/llface.h

indra/newview/llspatialpartition.cpp

indra/newview/llspatialpartition.h

indra/newview/lltextureatlas.cpp

indra/newview/lltextureatlas.h

indra/newview/lltextureatlasmanager.cpp

indra/newview/lltextureatlasmanager.h

indra/newview/llviewertexture.h