Add PBD::sys::path class that has a similar API to boost::filesystem::path but using glib/mm filesystem utility functions

Add ARDOUR::SessionDirectory class

Use SessionDirectory to create the session directory structure when creating a new session


git-svn-id: svn://localhost/ardour2/trunk@1874 d708f5d6-7413-0410-9779-e7cbd77b26cf

libs/pbd/SConscript

@@ -27,6 +27,7 @@ controllable.cc
 enumwriter.cc
 dmalloc.cc
 error.cc
+filesystem.cc
 id.cc
 mountpoint.cc
 path.cc