Remove the URI adapters. Few people use them by default and they can
allow insight into the internal networks of the server. If you want to
enable them, add (for example) `Paperclip.DataUriAdapter.register` to
your `config/initializers/paperclip.rb` file.

This is related to CVE-2017-0889.

Elsewhere fix CI: it's `s3.us-west-2` now, with a dot.

- Updates cucumber (https://github.com/cucumber/gherkin2/issues/320#issuecomment-139572490)
- Removes `bundle exec` from commands ran in cucumber steps
- Simplifies framework_major_version (we can assume it always is 4 or
  higher)
- Inline unneeded methods
- Fix some Ruby warnings

* update aruba methods for in_current_dir and check_file_presence
* switch rspec syntax from should to expect
* configure raise_in_transactional_callbacks if AR >= 4.2
* remove paperclip itself from Appraisal
This also updates Travis to use the default bundler (to enable caching) and to build primary rubies first

First off, sqlite3 needs to be exactly v1.3.8.
Need to make sure both racc and rubysl are in the Gemfiles.
RBX's File.join doesn't like nil at all.
RBX also doesn't like to remove a constant that doesn't exist yet.

This is a big one.

This change converts all of the existing tests from test/unit to RSpec.
It's been a long time coming, and was specifically prompted by the
inability of minitest to work with Appraisal across the various Rails
versions. Instead of ironing out that headache, converting to RSpec was
preferable (after initial probing).

Many assertions are still assertions and are housed in the Assertions
module, but they should be converted as they get touched. Similarly,
since we're touching all the tests/specs, we convert all the hashes from
1.8 syntax to 1.9 syntax.

Needs work for S3 Attachments.

This test will generate a basic Rails application, include Paperclip
into Gemfile, and call basic `has_attached_file` in the model. This will
make sure that we're not messing up any of the configuration and
integration for our gem and the Rails framework.