changing hamcrest dependency from optional to required

I updated my project to VRaptor 3.5.1 and when trying to upload to heroku I got:
`[ERROR] class file for org.hamcrest.Matcher not found`

I'm using fluent VRaptor Validation:
`this.that(notEmpty(name), "validation", "validation.required", this.i18n("user.name"));`

I think hamcrest dependencies should be required to avoid this kind of error.