SQL backend consolidation

[Ian Monroe]

Markey and I were talking about how we should perhaps drop Postgresql
and Sqlite, and just use MySQL embedded (in-process mysql support) and
perhaps support external MySQL as well.

The primary advantage would be we'd have less to support. Just MySQL.
Supporting sqlite, mysql and postgresql has been a real burden. The
secondary advantage is the MySQL 5 is almost a real database and it
has a lot of features we could take advantage of. Views, probably more
consistency checking. Currently we are held back by the limited subset
of SQL that sqlite supports. Also recent versions of sqlite have been
having corruption fixes.

What do folks think?
Ian