title: Gulp returns 0 when tasks fail
body: <p>I'm using Gulp in my small project in order to run tests and lint my code. When any of those tasks fail, Gulp always exits with return code 0. If I run jshint by hand, it exits with non-zero code as it should.</p>
  
  <p><a href="https://github.com/rbonvall/lambada/blob/f8aaa3a56c4b51f8655af0e5025a66229505d807/gulpfile.js" rel="noreferrer">Here's my very simple gulpfile</a>.</p>
  
  <p>Do I need to somehow explicitly tell Gulp to return a meaningful value? Is this Gulp's fault, or maybe the gulp-jshint and gulp-jasmine plugins are to blame?</p>