Tidy up the CSV importer.
Drupal: Also import items of type 'article'

Replaces #74
Drupal: Allow no password
Enki: Move EOS
Joomla: Allow no password
Marley: Validate that the data dir was passed and that it exists
Options now strings instead of symbols
Allow 'password' to default to "" and fetch it properly
Mephisto: Validate that dbname and user options are passed
Fix fetching of Wordpress options
Merge pull request #80 from jekyll/final-touchups

Tidy up the importers for a beta4 release