Leave+a+Group

== =__Leave a Group:__=
 * Synopsis**: A Faceplace User chooses to leave a group they had previously joined.
 * Actor/User**: Faceplace User
 * Preconditions**: User is logged in, has previously joined the group they now wish to leave, and is currently viewing that group's page.
 * Sunny Day Case**:
 * 1) The User clicks the clearly visible button specified for leaving the group located on each group page.
 * 2) The page reloads and the user is presented with a message informing them that they have successfully left the group.
 * 3) The User is removed from the group, which is reflected throughout the Faceplace webapp (such as it is not longer displayed as one of that User's groups).