Fix incorrect test case.

I forgot to include fixed => true.
Shift connection logic into the drivers.

This allows classes that only access the driver (like schema platforms)
to have access to lazy connection features. I think this also makes the
drivers better encapsulate their behavior. Before some of the
connected/connection logic was in the connection class which I think
will slowly become the datasource class, or a wrapper for the various
SQL based datasources at the very least.
Merge pull request #1268 from markstory/3.0-refactor-connections

3.0 - Re-factor connection handling logic