Added email path to DropboxResourceOwner
Merge pull request #396 from Padam87/master

Added email path to DropboxResourceOwner
Fixed redirectUrl handling

in OAuthUtils#getAuthorizationUrl
Merge pull request #398 from Padam87/redirectfix

Fixed redirectUrl handling in OAuthUtils#getAuthorizationUrl
Some cleanup of code:
- type-hint objects when possible,
- don't use container parameter in constructor
- reduce usage of container
- remove some code duplication
- made configuration a bit more readable
Refactor code to use Symfony OptionResolver component
Fix problem with twig extension after refactoring, cleanup after review