Fix markdown rendering
Remove unloadable from controller

https://github.com/thoughtbot/high_voltage/issues/68
Made the main library file loadable.

high_voltage.rb uses mattr_accessor methods, which are provided by
active_support. Normally these methods are provided by having Rails ran
beforehand, but this meant that high_voltage couldn't be loaded alone.

Added necessary require to address this.
Removed unused line from spec_helper.
Use older version of capybara.

Ruby versions older than 1.9.3 can't use capybara > 2.0.3.

Travis-provided error:

    Gem::InstallError: capybara requires Ruby version >= 1.9.3.
    An error occurred while installing capybara (2.1.0), and Bundler
    cannot continue.
    Make sure that `gem install capybara -v '2.1.0'` succeeds before
    bundling.
Removed trailing whitespace.

Because it's evil and evil must be purged.
Remove superfluous comment.

The previous commit message is enough.
Merge pull request #76 from thoughtbot/mm-remove_trailing_whitespace

Removed trailing whitespace.
Merge pull request #75 from thoughtbot/mm-old_ruby-fix

Use older version of capybara.
Merge pull request #72 from thoughtbot/mm-mattr_accessor-requiring

lib/high_voltage.rb should be able to be required.
Merge pull request #73 from thoughtbot/mm-spec_helper-tweak

Removed unused line from spec_helper.
Add rails 4.0.0.rc1 to appraisals, upgraded others

closes #77
Bump to 1.2.3
Allow page and action caching
Rails 4 caching compatible
Bump Rails version, and remove Ruby 1.8.7

* Remove Ruby 1.8.7 support
* Update Rails version to 4.0.0
Updated README
Update Travis CI Ruby and Rails versions

* Run certian versions Rails against Ruby 2.0
* Remove Rails 3.0.20 from CI
Update for Rails 4 compatibility

* Remove legacy style routing from README
* Remove specs for older style routing
* Update syntax highlighting in README
Clean up Appraisals and Rake