STORM-2082 Implement delete floater

indra/newview/CMakeLists.txt

indra/newview/llfloaterdeleteprefpreset.cpp

indra/newview/llfloaterdeleteprefpreset.h

indra/newview/llfloaterpreference.cpp

indra/newview/llfloaterpreference.h

indra/newview/llpanelpresetspulldown.cpp

indra/newview/llpanelpresetspulldown.h

indra/newview/llpresetsmanager.cpp

indra/newview/llpresetsmanager.h

indra/newview/llviewerfloaterreg.cpp

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

...view/skins/default/xui/en/panel_preferences_graphics1.xml

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