Adding support for ruby 2.0.0

This patch adds support for ruby 2.0.0.

The only thing that changed is that to create regexps with "odd" characters another parameter is needed, according to [the docs](http://www.ruby-doc.org/core-2.0/Regexp.html#method-c-new)

This parameters for `Regexp#new` are around since ruby 1.8.7, but there was no documentation. On ruby 2.0.0 they are now really needed, and so it is on documentation. So this patch is also retro-compatible.

Since there are no automated tests, it was simply evaluated by being successfully loaded.

If possible, release a new version of the gem with this changes, because I really need it.