Fixes #522 - Adjusts button_tag type attributes

- Adds missing `type: ‘submit’` to search filter icon buttons.
- Normalizes button type attribute to be first argument in all
button_tag instances.
- Removes name attribute on button_tags. Alternatively, the
`value` attribute could be added to identify which submit
button was clicked to submit the form. However, we currently
do not need to know which button was clicked.
Fixes #440 - updates Rails to 4.1.4

- Updates rails gem version to 4.1.4.
- Removes unused cassettes.
Removes unused cassettes

Removes cassettes that are not being auto generated.
Merge pull request #523 from codeforamerica/440-rails-41-upgrade

440 rails 41 upgrade