Merge pull request #52 from misja/master

Correct header authorization field
Fix test cases for #52
Delete useless header transform in extract_params.
Reformat logging.
Remove import log from utils.
Version bump 0.4.0
Fix for #53

set request.client from token upon validating bearer token.
Get request.client the right way. Add access_token on request. #53
Use existed add_params_to_uri instead of add_query
Remove test case for add_query
Fix test case, remove useless code of oauth1.
Add test case for #55
Fix lazy load token parameters. #55
Fix docs on save token.
Version bump 0.4.1
added google example
Add note for scopes in documentation.

related: https://github.com/lepture/flask-oauthlib/issues/58
Add credit for Brunon Roncha on google example.
Use String instead of Unicode, use Text instead of UnicodeText. Because
Flask-SQLAlchemy has convert them to unicode by default.
Fix another error in documentation.

related issue: https://github.com/lepture/flask-oauthlib/issues/56
Add support for OAuth2 state parameter