Updated the Gemfile to use https://rubygems.org and updated the bundle
too (Sinatra was throwing too many warnings otherwise).
- Added support for managing extra env settings you may want to use
  through subsequent requests.
  - There's an env method that allows managing those in the same way
  that `header` works.
  - Added tests for that too.
- Added a csrf method to automatically add everything a csrf
  token/request needs to work so you can save tons of lines in testing
  csrf enabled controllers.
Fixed the local load :S
Removed csrf.
Merge pull request #80 from dariocravero/csrf

Allow for custom env settings to be set