Fix i18n validation warning

According to StackOverflow[1], we need to set this explicitly in order to avoid
this warning:

  [deprecated] I18n.enforce_available_locales will default to true in the
  future. If you really want to skip validation of your locale you can set
  I18n.enforce_available_locales = false to avoid this message.

We set it to `true` to future-proof our apps, since that's what the default will
be in the future.

1: http://stackoverflow.com/questions/20361428/rails-i18n-validation-deprecation-warning
Update rails to 4.0.3
Test against Ruby 2.1.1
Add Awesome Print Gem

* I've found myself adding this to several projects recently
* using `ap model_object` results in a clearer output than `model_object.inspect` and is quicker to type
Add rake dev:prime task

* Task for development environment seed data.
* Run task in bin/setup.
* Add db:setup as a dependency of dev:prime.
* Add Factory Girl setup to dev:prime task.
* Only load development_seeds in development environment.
Remove RSpec fast-failing

When this is turned on, I'll run `rspec` and see only one failure. After fixing
it, I'll see another, and so on. Turning this off lets people know how many
failures they actually have. Seeing every failure can also help users with
debugging, since one change may have caused many failures, and seeing every
failure can help track down the bug.
Remove better_errors

* We're using unicorn as our default server
* better_errors is not compatible with unicorn
* Instead of error context, you just see "Session expired"
* The default Rails behavior is more reliable

https://github.com/charliesome/better_errors/issues/40
Upgrade New Relic agent for Postgres security fix

https://docs.newrelic.com/docs/traces/security-for-postgresql-explain-plans
Generate .travis.yml

We want to generate this file because:

* We're using Travis on a lot of projects
* It requires configuration to run builds and notify us
* We can skip some boilerplate by starting out with a sane config

The generated config makes sense because:

* It can run Ruby builds out of the box with our Ruby version
* It reduces noise for Campfire notifications
* It reduces volume in the queue by avoiding unnecessary branch builds

This also refactors handling of Ruby versions to move interpolation into
templates where possible.
Enable using just `t` (not `I18n.t`) in specs
Merging upstream.