dhb Medialist : created context menu function and moved lines which create

dhb  Medialist :  created context menu function and moved lines which create
     the context menu function there.  Call this function from
     MediaList::PgSeltreeWidgetClicked() so that the menu items only get added
     once instead of every time the tree gets repopulated.  Otherwise the popup
     menu ends up with repeats.
     Joblist : Set all flags of the table items to 0 so that the defaults of
     editable are not active.

git-svn-id: https://bacula.svn.sourceforge.net/svnroot/bacula/trunk@4513 91ce42f0-d328-0410-95d8-f526ca767f89