implement uniform answer to web client search

[mfrasca]

when the master client sends a request for matching objects, it expects objects of different types, which will behave more or less uniformly, or at least respecting the same idioms.

so an object in the results list should know how to present itself in the list, should know how to update the infobox, and should know of whatever objects depend from it.

I think we should implement these in the browse app, not in the distinct data apps (taxonomy, collection, garden).

the result could be

• a piece of html, or data to build it, similar to ghini's two lines representation;
• the url to ask for infobox data/view;
• a dictionary that associates a name to an url, to retrieve dependent data.

[mfrasca]

possibly good enough, let's move on to #7