Add professor_emailed to positions
Only email professor if they haven't been before
Only show work study if they have it on the index
Allow applicants to be deleted
Find position by identifier
Add link to position from professor show
Change checkboxes to radio buttons in positions view
Merge branch 'editing_positions'

* editing_positions:
  Change checkboxes to radio buttons in positions view
  Add link to position from professor show
  Find position by identifier
  Allow applicants to be deleted
  Only show work study if they have it on the index
  Only email professor if they haven't been before
  Add professor_emailed to positions

Conflicts:
	db/schema.rb (just the timestamps)
	spec/views/positions/edit.html.erb_spec.rb