Allow admins to assign raid members to more than 1 group

[caiters]

For purposes of splitting raids more equally so I don't have to open up a spreadsheet and do it there! :)

[caiters]

Other cool info to have would be

• number of people signed up as each role in the group (for purposes of backups)
• number of heroism, timewarp, etc in each group
• a number to show X dps per healer in group