Implementation of feature request 785

http://sourceforge.net/p/phpmyadmin/feature-requests/785/

The code stores the user information in pma_user_info in phpmyadmin database because as discussed in the mailing list, mending with mysql database is not a good idea, So for the time being i created the table in phpmyadmin database.

To change User Information, rather than going to priviledges page (as featured in the request),i Used Users Tab. 

Now, every user can change only his information. So if i have two users root and guest both belonging to host localhost, then root can only edit his info, but can view 'guests' info.

On Clicking the host column in Users tab, the user will be redirected to user_info via a GET Request(a href).

To edit the the details, a edit button is there which upon click displays a form where information can be entered and submitted via a Post request. It's a Legacy form submission, i wanted to use Ajax but Images don't get uploaded via jquery, so dropped the idea.

GUI may be bit weird, haven't applied any css. I will probably move the forms a bit towards right, however ideas are welcome.