Hack-ish switch from protected_attributes to strong_parameters

It's a very hack fix for switching to strong_parameters, but the only rspec tests that fail from it are the ones related to protected attributes. I couldn't get cucumber tests to run, so I don't know if any of those broke. :(

The most pertinent code is:
```ruby
def surveyor_params
  sliced = params.slice(:survey_code, :survey_version, :section, 
                        :finish, :response_set_code, :locale, :new_locale, 
                        :current_section, :surveyor_javascript_enabled, 
                        :authenticity_token, :utf8, :_method)
  sliced.permit!
end
```

P.S. This is my first pull request, yay!