Introducing the initial hooks for building the pathfinding linkset floater.

indra/newview/CMakeLists.txt

indra/newview/app_settings/commands.xml

indra/newview/llfloaterpathfindinglinksets.cpp

indra/newview/llfloaterpathfindinglinksets.h

indra/newview/llviewerfloaterreg.cpp

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

...iew/skins/default/xui/en/floater_pathfinding_linksets.xml

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