Improved 'Put user in course' and context menu for user list

- Changed the table displaying the users of a certain course to display action options in a contet menu instead of creating a new row
- Changed the layout of the 'Pu User in Cours' table to be searchable and have pagination
Fixed a bug when the webroot is another directory than '/'

The forms for mixed eval and simple surveys would generate the wrong URL when the application was installed in a subdirectory instead of the root of the webserver.
Fixed a bug when the webroot is another directory than '/'

Also affected Survey question creation
Fix for Ticket #517

- new check if any of the enrolled users role changed
- if user information changed in BB it now gets updated in iPeer