Handle case where presentation has no slot.
Display whether account is existing or newly created
Update styles for group registration alert messages
Create Accounts for registered users so that they can log in.
Switch order of views - easier to read pull request diff
Remove unneeded change
Fix group registration tests for Accounts
Merge pull request #362 from PyCon/program-export-bug

Program export bugfix
Merge pull request #360 from PyCon/group-registration

Group registration form
Dynamically calculate 'presenting' for fin aid applications