Improve cross python compatibility issues with little imports
Add index to AccessToken.token

Without an index, the retrieval of the access tokens performs a full table scan, and after just a few couple of thousands tokens it will significantly affect the performance.
Fixing minor typo in README.
Adding link to new mailing list in README.
Minor formating tweak to last README change.
Merge pull request #14 from dulaccc/fix-imports

Improve cross python compatibility issues with little imports
Removing need to client_secret during password grants for public clients

As discussed in issues #21 and #25. This provides a more rigerous check
of the circumstances required for the client_secret to forgone.
Not sending a refresh_token to public clients requesting password_grants
Public and private clients can now have different expiry times

Public clients often wish to have shorter expieration times
Clean up and PEP8 for #41.
Bumping version to 0.2.7-dev to avoid ambiguity in an established package.
Addressing #28 by replacing the BSD license reference with MIT to match what's in the repo.
Merge pull request #31 from gotche/master

Add index to AccessToken.token
#29 - Remove trailing slash that was causing installs to fail on Windows.
Fixes #32 - Add `token_type` to access token response to conform to section 4.2.2 of the OAuth 2.0 specification.
Adding a License section to README.
implement OAUTH_CLEAN_EXPIRED, clean as you go

this avoids keeping around unneeded/no-longer usable objects. it's optional
defaulting to False, the current behavior.

adds a setting OAUTH_CLEAN_EXPIRED that optionally cleans out objects as
they're expired which should keep the size of the grant, access, and refresh
token tables in check.

once grants are used they are deleted. and once a RefreshToken is used both
it and its corresponding AccessToken are deleted.
Use `constants` instead of going directly through settings when invalidating tokens and grants. This also replaces 'clean' with 'delete' for the new setting to be more clear as to what's being done under the hood.
Merge pull request #50 from caffeinehit/pr/48

Implement OAUTH_DELETE_EXPIRED setting
Fix #26 by checking for invalid data before attempting access.