message: Doxygen: Adding statement about default container handling
diff: @@ -150,4 +150,18 @@ For nearly all uses, they should use the following names:
  | Clusters | "caloClusters" | "CaloClusters" |
  | Tracks | "tracks" | "Tracks" |
  +Default containers as listed above can be accessed directly passing the argument *usedefault* as name of the
  +input containers. The example below demonstrates this for the cluster container:
  +
  +~~~{.cxx}
  +AliClusterContainer *clustercont = new AliClusterContainer("usedefault", "myclustercont");
  +~~~
  +
  +or
  +
  +~~~{.cxx}
  +AliAnalysisTaskEmcal *emcaltask = new AliAnalysisTaskEmcal("emcaltask", kTRUE);
  +AliClusterContainer *clustercont = emcaltask->AddClusterContainer("usedefault");
  +~~~
  +
  */
  