added Twitter floater for ACME-1146, ACME-1147, ACME-1148, ACME-1149, and ACME-1150

indra/newview/CMakeLists.txt

indra/newview/llfloatersnapshot.cpp

indra/newview/llfloatertwitter.cpp

indra/newview/llfloatertwitter.h

indra/newview/llsnapshotlivepreview.cpp

indra/newview/lltwitterconnect.cpp

indra/newview/llviewerfloaterreg.cpp

indra/newview/skins/default/xui/en/floater_twitter.xml

indra/newview/skins/default/xui/en/menu_viewer.xml

indra/newview/skins/default/xui/en/panel_twitter_account.xml

indra/newview/skins/default/xui/en/panel_twitter_photo.xml

indra/newview/skins/default/xui/en/strings.xml