Updated the Travis configuration file.

This has been updated based on the .travis.yml of rubinius-compiler.
Removed the spec_helper require for Travis.

This file doesn't exist so there's no point in loading it.
Import MRI Git commit fc3c52e.
Added basic specs for URI.decode_www_form.
Basic specs for URI.decode_www_form_component

These are based on the wonderful tests of MRI itself, which can be found at
<http://git.io/H0WoKA>.
Basic specs for URI.encode_www_form_component
Basic specs for URI.encode_www_form
Merge pull request #2 from rubysl/mri-21-import

MRI 2.1 updates