Speed up dictionary based name and asset lookup

indra/llappearance/lltexlayer.cpp

indra/llappearance/lltexlayerparams.cpp

indra/llappearance/llwearabletype.cpp

indra/llcommon/llassettype.cpp

indra/llinventory/llfoldertype.cpp

indra/llinventory/llinventorysettings.cpp

indra/llinventory/llinventorytype.cpp

indra/newview/llinventoryicon.cpp

indra/newview/llviewerassettype.cpp

indra/newview/llviewerfoldertype.cpp

indra/newview/llviewerinventory.cpp

indra/newview/rlvactions.cpp

indra/newview/rlvcommon.cpp

indra/newview/rlvfloaters.cpp

indra/newview/rlvhandler.cpp

indra/newview/rlvhelper.cpp

indra/newview/rlvmodifiers.h