* Made XGlobalEventBroadcaster inherit document::XDocumentEventBroadcaster/
  Listener replacements for obsolete document::XEventBroadcaster/Listener.  This
  means some client sides unfortunately still need to use UNO_QUERY_THROW to
  obtain the obsolete interfaces; those client sides should be cleaned up to use
  the replacement interfaces instead.

* Added @since tag (even to unpublished entities, on "it doesn't hurt" grounds).

* Made client sides use XGlobalEventBroadcaster directly instead of querying for
  its super-interfaces.

* Replaced new uses of comphelper::ComponentContext::getUNOContext with
  comphelper::getComponentContext (see 03a9f139
  "ComponentContext::getUnoContext -> getComponentContext simplification;" I
  intend to get rid of comphelper/componentcontext.hxx much sooner than of
  comphelper/processfactory.hxx).

Change-Id: I6d971ebdaea83d0c3fa9ba299fb6b37e58cdfe9b