[ardour-dev] recent SVN commits

[Paul Davis]

    * rationalize editor scroll + zoom operations (code level, should be
invisible to user)
    * fix assignment of remote control IDs
    * save playhead  + edit cursor and restore on session load
    * fix coloration, editability and thread issues with big clock
    * fix up xfade logic and use shared_ptr for xfades
    * fix audio clock restore
    * provide XMLNode::property (string) 
    * speed up the property methods by not scanning the map twice.  

    * rev 1305