Admin side finalizing changes.

Implemented changes -->
-- Row highlighting on enable/disable in role and user manager
-- Delete role and user added in role and user manager
-- Refresh db user added in role manager to easily recreate a db user if
it does not exist.
-- Change role in bvicam_admin added.
-- Implementation for user_registrar added in new user creation
-- App wise sessions implemented. So now indiacom_online and
bvicam_admin can be opened simultaneously without any clashes.
-- application_master table added.
-- user_event_role_mapper table modified. Now it maps only a user and an
application. (Name will be changed in next commit to user_role_mapper).
-- application_id field added to role_master to map role to application.
-- Some exception handling incorporated.
-- sudo privilege elevation implemented for certain privileged models
and functions. (eg. LoginModel, AccessModel, (create,drop,grant,revoke
user)etc.)
-- privilege.php filled for user manager and role manager.

To be implemented -->
-- News table needs to be modified
-- user_event_role_mapper rename to user_role_mapper in db and models
and controllers.
-- navigation functionality for bvicam_admin
-- fully fill privilege.php
-- An error occurs when editing a disabled role.
-- Integrate all paths into path.php
-- Exception handling to be implemented fully.
-- Rollbacks.
-- Application Manager admin UI
-- Event Manager admin UI
-- Edit user details in User Manager -> Edit User