Added queue commands :push and :pop.
Added new hinting mode to put links into queue.

Also added new default keybinding to open oldest queued item in current window
'ctrl-p'.
Fixed wrong bookmark lookup.

If the completion for bookmarks was started with given tags, there where also
items displayed that have no tags set. This patch fixes the regression so that
only those bookmarks are shown thats tags match the request, all other
bookmarks can only be seen when the completion is started without tags like
':open !<tab>'.