merge QAR-1579: texture-cleanup-1.

indra/integration_tests/llui_libtest/llui_libtest.cpp

indra/llrender/CMakeLists.txt

indra/llrender/llfontgl.cpp

indra/llrender/llfontgl.h

indra/llrender/llimagegl.cpp

indra/llrender/llimagegl.h

indra/llrender/llrender.cpp

indra/llrender/llrender.h

indra/llrender/lltexture.cpp

indra/llrender/lltexture.h

indra/llui/llcombobox.h

indra/llui/lliconctrl.h

indra/llui/llmultislider.cpp

indra/llui/llprogressbar.cpp

indra/llui/llresizehandle.h

indra/llui/llscrolllistctrl.h

indra/llui/llslider.cpp

indra/llui/llslider.h

indra/llui/lltexteditor.cpp

indra/llui/llui.cpp