title: Overwrite the NotBlank Constraint Message on symfony2.1 globally?
body: <p>How can I overwrite the <code>NotBlank</code> constraint message <code>This value should not be blank</code> globally throughout the Symfony 2.1 application?</p>
  
  <p>I've tried with <code>validators.en.yml</code> files, but this works only if I set for every NotBlank constraint in my <code>validation.yml</code> files to a constant like <code>not.blank.field</code> - but is too much to modify.</p>