Fixed GestureTable build error

GestureTable build error in my system (OSX 10.8.5, RubyMotion 2.11, Xcode 5.0)

```
$ rake
Build ./build/iPhoneSimulator-7.0-Development
Compile ./app/gesture_recognizer.rb
Compile ./app/UITableView_extensions.rb
Compile ./app/transformable_cells.rb
Compile ./app/UIColor_extensions.rb
Compile ./app/app_delegate.rb
Compile ./app/view_controller.rb
Create ./build/iPhoneSimulator-7.0-Development/Gesture Table.app
Link ./build/iPhoneSimulator-7.0-Development/Gesture Table.app/Gesture Table
Create ./build/iPhoneSimulator-7.0-Development/Gesture Table.app/PkgInfo
Create ./build/iPhoneSimulator-7.0-Development/Gesture Table.app/Info.plist
Copy ./resources/Default-568h@2x.png
Create ./build/iPhoneSimulator-7.0-Development/Gesture Table.dSYM
Simulate ./build/iPhoneSimulator-7.0-Development/Gesture Table.app
<PullDownTableViewCell 0xa6818e0> method `tintColor' created by attr_reader/writer or define_method cannot be called from Objective-C. Please manually define the method instead (using the `def' keyword).((null))
```

I fixed it.