ruby-install 0.3.1

### 0.3.1 / 2013-09-23

* Always use the system's `stat` command on OSX (@paul).
* Do not assume homebrew is installed at `/usr/local/bin/brew`.
* Properly quote/expand `$CONFIGURE_OPTS` to prevent incorrect word-splitting
  (@pbrisbin).
* Style changes.

#### ruby

* Download from the new http://cache.ruby-lang.org/ CDN (@hsbt).
* When installing ruby 1.8.x, rubygems-2.1.3 will now be installed.
* Added the MD5 checksum for ruby-2.1.0-preview1.tar.bz2.
* Added the `2.1` and `2.1.0` version aliases for 2.1.0-preview1.

#### rubinius

* Support the new 2.x installation process.
* Added MD5s and versions for `2.1.0` and `2.0.0`.
* Removed support for `2.0.0-rc1`.