Be able to easily customize the eclipse-wtp facet version

I think

eclipse {
  wtp {
  facet {
    facet name: 'jst.web', version: '3.0'
    facet name: 'java', version: '1.7'
    facet name: 'wst.jsdt.web', version: '1.0'
  }
 }
}

already does that.