added migrations for ptaeos to categories, default category for locations, and category per location
adds billing code to view
adds billing code and location-category association to edit and show views
add default payform category to department settings view
payforms are now exported grouped by ptaeo per category and person, summary on payform set page
Merge branch 'ptaeo' of github.com:YaleSTC/shifts into ptaeo
simplifies code for payform sorting
make a locations payform category required
rounds hours to nearest 15 minutes by category
payform show page - category sums are now rounded
shifts now add to category defined on location
location required wrong attribute, corrected
Merge branch 'ptaeo'