Log Message:
Update ruby-rack-test to 0.6.3.

== 0.6.3 / 2015-01-09

* Minor enhancements

  * Expose an env helper for persistently configuring the env as needed
    (Darío Javier Cravero #80)
  * Expose the tempfile of UploadedFile (Sytse Sijbrandij #67)

* Bug fixes

  * Improve support for arrays of hashes in multipart forms (Murray Steele #69)
  * Improve test for query strings (Paul Grayson #66)