Tweak gruntfile to allow livereload to happen without a page refresh

Based on http://stackoverflow.com/questions/19005847/how-can-i-get-grunt-watch-livereload-to-reload-sass-css-without-a-full-page-refr this tweak allows you to use livereload for sass files without forcing a full page refresh
Tweak gruntfile to allow livereload to happen without a page refresh

* origin/pr/11397:
  Tweak gruntfile to allow livereload to happen without a page refresh