Update to RSpec 3.0.0

Updates to Rspec 3 and applies transpec gem updates to the test suite.
Streamline and organize RSpec setup.

- Streamline `rails_helper` and `spec_helper` to only include what we
use.

- Move capybara and VCR config to their own files to keep things
organized.

- Delete `.rspec` and add it back to `.gitignore`.
Remove active_record line from production.rb

We don't use active_record or a DB in this app.
Merge pull request #520 from codeforamerica/519-upgrade-rspec

Update to RSpec 3.0.0
Fixes #495 - Adds input clear button

- Adds search input manager for handling input clear button—little (x).
- Disables autocomplete because field highlight color can’t be
overridden.
- Removes unused data-list attributes.
- Adds tests for clearing the input fields.
Refactors class names

- Normalized button and form id/class names using the specificity
principle.
- Removes unused classes from submit/reset buttons.