Merge branch 'DRTVWR-559' of https://github.com/secondlife/viewer

indra/llprimitive/llgltfmaterial.cpp

indra/llrender/llimagegl.cpp

indra/newview/llenvironment.cpp

indra/newview/llfloaterenvironmentadjust.cpp

indra/newview/llfloatertools.cpp

indra/newview/llmaterialeditor.cpp

indra/newview/llmaterialeditor.h

indra/newview/llpaneleditsky.cpp

indra/newview/llpanelface.cpp

indra/newview/llreflectionmapmanager.cpp

indra/newview/llreflectionmapmanager.h

indra/newview/lltexturectrl.cpp

...wview/skins/default/xui/en/floater_adjust_environment.xml

...newview/skins/default/xui/en/panel_settings_sky_atmos.xml