Added ability to upload csv form to exzweight.  Unfortunately, it does
not currently handle entries that match in the database and on the
uploaded csv file.

There were a lot of routing problems due to my inexperience.  They seem
to have been overcome, and hopefully the changes I made will not be a
problem in the future (*cross fingers*)!

 On branch experimental
 Changes to be committed:
	modified:   app/controllers/exzweights_controller.rb
	modified:   app/models/exzweight.rb
	modified:   app/views/exzweights/_form.html.erb
	modified:   app/views/exzweights/edit.html.erb
	modified:   app/views/exzweights/index.html.erb
	modified:   app/views/exzweights/show.html.erb
	modified:   config/routes.rb
	deleted:    db/migrate/20140602161910_intro_pri_key.rb
	deleted:    db/migrate/2014060216400_return_id.rb
	modified:   db/schema.rb