Make difference between Users and Groups more obvious

Issue #8 resolved
MattS created an issue

When I tell people to contact their project admins and show them the Project Roles tab they see the project admins all mixed in with users from the jira-administrators group. It would be great to display the individual users first and then the users from the groups in the role. Or make the difference obvious in some other way.

~Matt

p.s. Great add-on, I recommend it to many of ServiceRocket's customers