Merge downstream code and become 3.7.18

.hgtags

indra/newview/VIEWER_VERSION.txt

indra/newview/app_settings/settings.xml

indra/newview/app_settings/settings_per_account.xml

indra/newview/llagent.cpp

indra/newview/llappviewer.cpp

indra/newview/llfloaterpreference.cpp

indra/newview/llfloaterpreference.h

indra/newview/llloginhandler.cpp

indra/newview/llpanellogin.cpp

indra/newview/llpanellogin.h

indra/newview/llstartup.cpp

indra/newview/llvoiceclient.cpp

indra/newview/llvoiceclient.h

indra/newview/llvoicevivox.cpp

indra/newview/llvoicevivox.h

indra/newview/skins/default/textures/textures.xml

...wview/skins/default/textures/widgets/PushButton_Login.png

.../skins/default/textures/widgets/PushButton_Login_Over.png

...ins/default/textures/widgets/PushButton_Login_Pressed.png