remove "required" fields for administrator entry of participants

[GoogleCodeExporter]

Sometimes an administrator needs to add an entrant quickly (such as during a 
day-of-competition situation) and does not have a phone number/email address 
etc.  Might be easier if the "required" nature of these fields could be 
overridden by the admin.

Low priority because an easy workaround is to just type in dummy information.

Original issue reported on code.google.com by ragiaqui...@gmail.com on 5 Jan 2014 at 12:39