Cadence/ClearCase integration: improvements for hierarchy manager

In the context of the Cadence/ClearCase integration we'd like to see some improvements of the "Manage Hierarchy" functionality:

1. Tree vs. Flat display
the current implementation shows the entire hierarchy as a flat list; this makes it hard to discern which hierarchy level each cell(view) has in the hierarchy. Since this property anyway is known from iterating the hierarchy, we propose to use either a tree view, or at least indenting to show the hierarchy depth and the parent-child relationships. This helps a lot to give the developer at first glance an idea which sub- and sub-sub-hierarchies exist for the selected hierarchy.

2. Parent hierarchy view
The current "Manage Hierarchy" menu descends from the selected cell(view) down towards the leaf cell(view)s, and presents the collection to the user. In addition to that, users are interested in a "parent" view, which would search the current workarea context (i.e. all known and visible libraries and their possible cellviews) for references to the selected cell(view). Example: if a subblock "S" is instantiated in cells "A" and "B", both of which are instantiated on top level, the "parent" view of cellview "S" would show the toplevel, and the two cells "A" and "B" (indented or as a tree), and below A and B the subblock "S".

In both hierarchy views, the user would be able to select any set of the listed cell(view)s and then operate action on the selection: label, checkout, checkin, cancel, and open.