Merge pull request #143 from cloudson/patch-1

Update copyright date to 2014.
Updates README introduction.

With the discussion on reddit about Respect/Validation being the most
awesome validation engine and also with a more accurate number of
current rules.
Authors on composer.json are now resumed to a link.

Instead of keeping the file up to date and confusing ourselves with
changes to the file on the version control, the author's not point to
GitHub list of contributors.
Add PHPUnit as a development dependency on composer.json.

We can always use Respect/Foundation, but with that component on
composer.json I think it is easier for new contributors to get things
running on their development environment.
Fix Symfony validation rule.

The API of Symfony\Component\Validator changed more than 2 years ago, so
this validation rule wasn't working for quite a long time.

This fixes the validator to work with versions >= 2.1 of
Symfony/Validation as the change on composer shows us. Although a bug
fix, this breaks compatibility with people already using this validator.

I was astonished to not find any tests for that validator also. :(
With those tests we can ensure that any change on the component API will
be noticed by us.