Persistent data management tools

[linas]

This is a very vaguely-defined feature request: we need some sort of tool suite to manage selected subsets of data from oen or more atomspaces, via SQL or via scheme dumps to files.

The general issue is that as the robot accumulates experiences and learns things, there needs to be some way of saving and restoring this stuff (yes, SQL can do this, yes, a dump of atomspace to file can do this) but such save/restore is a very blunt instrument. We need a "data management" solution: a way of saying what to save, what to restore, from where, which snapshot.

Its unclear how to solve this, because we have only marginal use-cases so far. @inflector