merge changes from viewer-beta

doc/contributions.txt

etc/message.xml

indra/cmake/GetPrerequisites_2_8.cmake

indra/cmake/LLAddBuildTest.cmake

indra/llaudio/llaudioengine.cpp

indra/llcommon/llfile.cpp

indra/llcommon/llfile.h

indra/llcommon/llversionviewer.h

indra/llimage/llpngwrapper.cpp

indra/llimage/llpngwrapper.h

indra/llmath/llbbox.cpp

indra/llmath/llbbox.h

indra/llmessage/llregionflags.h

indra/llui/llfloater.cpp

indra/llui/llmenugl.cpp

indra/llui/llnotifications.cpp

indra/llui/llurlentry.cpp

indra/llui/llurlentry.h

indra/llui/tests/llurlentry_stub.cpp

indra/newview/CMakeLists.txt