Split up event notification, make sorting on username work.
Send notification to admin when a user enters 'pending' state.

Also fixes a bug where message was not sent to user when entering 'denied'
state unless the user was previously in 'granted'.

Send notification to admin when a user enters 'pending' state.

Pylint cleanup.
Include the URL to the course creator admin table.
Merge pull request #598 from edx/christina/email-studio-request

Send e-mail to STUDIO_REQUEST_EMAIL when user requests course creator privileges