Revert "Fix #31: cannot start empty payment"
There are javascript issues on other pages as a result of these changes

This reverts commit 13556f366533241467753a7aefbd593d76413409.
remove ^I characters
Add AgeGroupType model/controller/views
add rails_admin gem. Allows accessing all models/data via the /rails_admin path. Also provides a good interface to the papertrail information
update bullet, spreadsheet and paper_trail gems
Add AgeGroupEntry controller/views/Model
Adjust the way that age group entries see the 'gender' options
add ability to retrieve the correct age_group_entry given an age/gender
Replace 'multiple' with 'event_category' concept. Adds the ability to specify 'event categories', and have registrants choose them
Link the event page to the event category page, and fix a render issue
add the ability to associate an age_group_type with an event_category
Use spaces instead of ` for README
Use spaces instead of ` for README
add ability to view registrations by age group entry FOR a single event_category
Add 'name' to Event, replacing the primary_choice.label with the event.name
remove unused code from the attending block
Add event_category_id association to the registrant_choice model, so that we can directly join between event_category and registrant_choices
update notes
Allow printing of multiple categories' members in the events page
Count the competitors in each event_category