Updating project helpers for upcoming updates.
Reorganization of submodules to support additional data stores.

- Worker broken into two submodules, 'pg' (postgresql workers) and 's3'
  (s3 workers)
- New blobstore submodule added to help abstract away specifics of
  datastore interaction
Adding support for Windows Azure Blob Service as a datastore.
Merge pull request #47 from socrata/azure-support

Enabling easy addition of new data stores, adding Windows Azure Blob Service support
Add Brian Oldfield as a contributor.
Fix __all__ to use strings

Also alphabetize all the import and __all__ list lines, now that some
of the lists of exported functions are getting long enough to be
harder to scan.

Alex Gaynor <alex.gaynor@gmail.com> caught this systematic mistake of
mine in code review.
Fixes #50