OAuth Twitter: Access Twitter API on behalf of an user

This class can be used to access the Twitter API on behalf of an user using OAuth.

It uses the Zend Framework OAuth consumer package to generate a token for accessing the Twitter API on behalf of the current site user.

The class redirects to use to the Twitter site to verify the user permission and handles the request to receive the validated OAuth token.

From then on, the class can access the Twitter API using the OAuth token to perform several types of actions like: updating the user status, get the user followers and friends.