lib/hacks/grid-utils.js
function selectorsEqual (ruleA, ruleB) {
  return ruleA.selectors.some(sel => {
    return ruleB.selectors.some(s => s === sel)
  })
}
function selectorsEqual (ruleA, ruleB) {
  return ruleA.selectors.some(sel => {
    return ruleB.selectors.some(s => s === sel)
  })
}
function selectorsEqual ( ruleA , ruleB ) { return ruleA . selectors . some ( sel => { return ruleB . selectors . some ( s => s === sel ) } ) }
check if selector of rules are equal
@param  {Rule} ruleA
@param  {Rule} ruleB
@return {Boolean}
check if selector of rules are equal