PATH-304,PATH-205: Initial reworking of the navmesh download functionality.

indra/newview/CMakeLists.txt

indra/newview/llfloaterpathfindingbasic.cpp

indra/newview/llfloaterpathfindingconsole.cpp

indra/newview/llfloaterpathfindingconsole.h

indra/newview/llfloaterpathfindinglinksets.cpp

indra/newview/llnavmeshstation.cpp

indra/newview/llnavmeshstation.h

indra/newview/llpathfindingmanager.cpp

indra/newview/llpathfindingmanager.h

indra/newview/llpathfindingnavmesh.cpp

indra/newview/llpathfindingnavmesh.h

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