Bug 635009 - Add one-way AD sync capability
    
    This patch adds one-way AD sync capability. A new "oneWaySync"
    configuration attribute can be added to a sync agreement to specify
    which direction one-way sync should work (values of "toWindows" and
    "fromWindows" will be accepted).
    
    Internally, the server will just skip pushing/pulling updates depending
    on the direction that sync is configured for.  We will still update the
    RUV as if entries were actually synced.
    
    One can introduce inconsistencies by updating synced entries on the
    receiving side when using one way sync.  This should be avoided by
    restricting update access to synced entries.