Update rspec-rails version to 3.0.1 & update specs.

- Clean up and add more specs to models

- Replace attribute_normalizer with the much lighter auto_strip_attributes

- Make sure to strip all attributes that require it, and use the squish option
Merge pull request #172 from codeforamerica/upgrade-rspec

Update rspec-rails version to 3.0.1 & update specs.