Rails 4 Updates and Dropdown Fixes

A few things fixed in this pull request:
* Rails 4 compatibility with Ruby 2 ensured, primarily by removing attr_accessible parameters as they are unnecessary
* Creation of Province, City, and District objects in rake task now use strong parameters
* When a new Province is selected in the drop-downs, City used to be the only dropdown that would update. This update forces both City and District to update the drop-downs.
* Extra whitespace eliminated

Thanks a ton for this awesome gem, hopefully this helps folks out.
Trey Springer
Enova International