In order to remove code duplication, and as prove of concept,
I redid the linden_genepool archetype export and import (from the Edit
Appearance Floater), using AIXML and AIAlert.
The import/export code did shrink significantly, and became a lot
simpler. Although a new file pair (aixmllindengenepool.{cpp,h}) is
added to define the (de)serialization of the linden_genepool XML format,
that code is now centralized in one place, and still a lot simpler.
As a bonus however, every possible error is now semi-automatically
reported to the user with all details that might help to overcome
the problem, like file names and system errors.
