Merge into viewer/viewer-20 yesterday's lindenlab/svn-imports-viewer-20

doc/contributions.txt

indra/integration_tests/llui_libtest/CMakeLists.txt

indra/llcommon/indra_constants.h

indra/llcommon/lllslconstants.h

indra/llcommon/llstring.cpp

indra/llmath/llcamera.cpp

indra/llmath/llcamera.h

indra/llmath/llrect.h

indra/llmath/llvolume.cpp

indra/llmath/v3math.h

indra/llmessage/lliobuffer.cpp

indra/llprimitive/llprimitive.cpp

indra/llrender/llgl.cpp

indra/llrender/llgl.h

indra/llrender/llimagegl.cpp

indra/llrender/llimagegl.h

indra/llrender/llrender.cpp

indra/llrender/llrender.h

indra/llrender/llrendertarget.cpp

indra/llrender/llrendertarget.h