[okfn-help] vdm module refactoring

[Martijn Faassen]

Hi there,

I thought I'd report on the less interesting work I did on vdm too,
the module refactoring. In summary:

vdm.sqlobject is gone
vdm.sqlalchemy is there, but only for backwards compatibility,
importing from vdm

vdm is now where you import from, not vdm.sqlalchemy.

I've also taken the opportunity to:

* gather all imports scattered through the module to the top of the
module. This makes it easier to analyze import relationships

* change all "from import *" into explicit imports, except in
__init__.py. This also makes it easier to analyze import
relationships.

* run pyflakes and remove a lot of unused imports. (there are still a
bunch of unused variable assignments in tests, but I mostly left them
intact)

Regards,

Martijn