code: function(properties, value, equals)
    {
      var where = createWhere( properties, value, equals );
  
      var hasChanges = function( model )
      {
        return where( model ) && model.$hasChanges();
      };
  
      return this.contains( hasChanges );
    }
docs: Returns whether this collection has at least one model with changes. An
  additional where expression can be given to only check certain models.
  
  @method
  @memberof Rekord.ModelCollection#
  @param {whereInput} [properties] -
  See {@link Rekord.createWhere}
  @param {Any} [value] -
  See {@link Rekord.createWhere}
  @param {equalityCallback} [equals=Rekord.equalsStrict] -
  See {@link Rekord.createWhere}
  @return {Boolean} -
  True if at least one model has changes, otherwise false.
  @see Rekord.createWhere
  @see Rekord.Model#$hasChanges