code: function(keyName, increment) {
      if (!increment) { increment = 1; }
      set(this, keyName, (get(this, keyName) || 0)+increment);
      return get(this, keyName);
    }
docs: Set the value of a property to the current value plus some amount.
  
  ```javascript
  person.incrementProperty('age');
  team.incrementProperty('score', 2);
  ```
  
  @method incrementProperty
  @param {String} keyName The name of the property to increment
  @param {Object} increment The amount to increment by. Defaults to 1
  @return {Object} The new property value