Added mac specific ardour2_mac_ui.rc file
Fixed some memory leaks in add_instant_xml() usage.
Added EXTRA_WARN scons option for pedants.
Reformatted xml++.cc into something that wouldn't drive me insane.
git-svn-id: svn://localhost/ardour2/trunk@686 d708f5d6-7413-0410-9779-e7cbd77b26cf