Graceful fallback for non-rackspace / swift providers

Only try to add the region if the provider allows for it from
the given PROVIDER_TO_REGION mapping
Bump minimum version for apache-libcloud dependency to 0.13.0.
Explicit None when grabbing the forced region
Merge pull request #8 from racker/add_region_as_an_option

Added region as an option for file-syncer
Merge branch 'master' of github.com:Kami/python-file-syncer
Update changes.
Update readme.
Bump version.
Merge branch 'master' of https://github.com/Kami/python-file-syncer