Patch to add Manual Sync option to civicrm_group_roles as batch process

For some reason civicrm_member_roles includes a manual sync and cron option, but civicrm_group_roles does not. This patch adds a similar tab to civicrm_member_roles. It is a bit different from civicrm_member_roles in that the form passes the processing off to a batch process. This was written for CivicActions as part of the Manhattan Neighborhood Network's upgrade from CiviCRM 1 -> 4.