Delete the implicit content type header assignment

I don't know what was the reason for this, but Rails knows better
what the response content type really is.
Merge pull request #42 from amw/remove-content-header

Delete the implicit content type header assignment
Fix admin preview.
Merge pull request #43 from amw/fix-admin-preview

Fix admin preview.
JRuby compatibility. We require RedCloth 4.2.7 here, since it is the latest version of the gem that has 'java' platform support.

jruby-openssl may not be necessary, but I've thrown it in there for a good measure.
Relax RedCloth constraint, bump to 4.2.8.
Remove hpricot, upgrade nokogiri for windows compat (I hope). Fixes #34.
In-memory database for testing, and create database.yml for travis ci.
Fix typo in travis config.
Revert in memory db, try a new strategy for running the build.
Migrate rather than load schema.

schema.rb should probably be checked in but isn't for some reason, not
investigating now.
Better mocking to try and appease travis (can't make it fail locally...)
Last commit worked, forgot admin/posts spec though.
Argh s/model/mock_model/g
Start Rails 3.2 upgrade
Upgrade Cucumber configs, fix feature steps, and add cucumber-websteps gem
Reorganize assets to serve through Rails' asset pipeline
Doh! Readd Webrat for RSpec requests. Capybara does not support POST
Replace exception_notification plugin with a gem as Rails 2.3-style plugins are being deprecated
Update Gemfile. Rails 3.2.0 was officially released