Refactors drupal_uploader.py to support multiple database and blog types.
Refactors drupal_uploader.py to support multiple database and blog types.

Provides initial support for using either MySQL or PostgreSQL databases, and
refactors import code into an abstract base class and drupal-specific
implementation to make room for adding support for other blog types.

Note this is all totally untested, since I don't have a drupal blog to import
from.

bcherry/adequatelygood,bcherry/adequatelygood,bcherry/adequatelygood,bcherry/adequatelygood,bcherry/adequatelygood