Added html to the prize format help text
Using settings site prefix in admin pages
Added more html to the prize form help fields
Fixed admin processing pages to work with site prefix from settings correctly
Fixed merge donors form
Added safe tags to html help text
Added a prize contributor auto-mailing system
Added nullability to prize contribution fields
Fixed some errors and inconsistency in randgen

Also added a maxwinners field to randomly assign more than one winner on a
generated prize set
Added tests for the prize contributor automailer