Merge pull request #760 from magfest/import_attendees

Export and Import Attendees
Prevent 500 error for unassigned badges

In some cases, badge-saving doesn't go through the normal checks to
ensure data validity. This converts an empty string to None for
birthdates to stop a 500 error from happening upon insertion.
Replace group.new_badge_type

Replaces the new_badge_type property, which was hardcoded to only care
about Guest badges. Groups now had a drop-down for badge type that
affects only new badges.
Show admin notes on group index page

Adds a column to the group index page so notes can be viewed
at-a-glance.
Always display group management link

Moves the "Link for group leader" outside of a sorted_attendees check,
so it will display even for empty groups.
Fix group badge claiming

The form is still ugly, but at least it has all the elements on it.
Merge from ac-staging

Resolve conflicts for PR.
Fix design for register_group_member

Adds a missing form tag, so now register_group_member looks good.
Merge pull request #802 from magfest/dealer_changes

Group fixes for AC
remove collapse feature from attendee table
disable footable sorting on attendee table, because that table is sorted server side
Merge pull request #804 from magfest/bootstrap

remove collapse feature from attendee table
Remove the ability to delete accounts

Comments out any actual deletions of data for attendees, groups, and
admin accounts. Everything else currently behaves as if the deletions
are completed.
Allow deletion of Unassigned badges

Allows admins to remove "Unassigned" badges, which don't have data. Also
adds support for removing badges from a group where they would normally
be deleted.
Remove syntax error

I missed commenting out an empty for loop.
Add tracking for deletion attempts

AnthroCon wants to know when someone TRIED to delete an attendee, even
though the deletion doesn't go through. This adds manual tracking so it
shows up in the FODC.
Fix group unassigning

Uber was creating a badge with a duplicate number when you unassigned a
badge from a group. Now it just adds an extra badge to the group
instead.
Merge pull request #808 from magfest/change_deletion_to_inactive

Remove the ability to delete accounts
Allows unassigned badges to be removed

Allows straight removal of unassigned badges, and ensures that new
badges created in a group to replace removed ones are the same type.
Change tracking message for manual deletions

Changes "Deleted" to say "Invalidated" because this is what these
functions will do in the future.