code: function pushDeepValue(target, path, value) {
      var deepRef = getDeepRef(target, path);
      if (!isWhat.isArray(deepRef))
          return;
      return deepRef.push(value);
  }
docs: Pushes a value in an array which is a deep property in an object, based on a path to that property
  
  @param   {object} target   the Object to push the value on
  @param   {string} path     'path/to.sub.prop'
  @param   {*}      value    the value to push
  @returns {number}          the new length of the array