Removing some warnings

- Accessing the isa pointer is deprecated: https://github.com/mindsnacks/moai-dev/commit/91e5d4216bb0bef16b099b5530a955d4bb4e7f60
- Method expects to return something: https://github.com/mindsnacks/moai-dev/commit/c2a93c2596f6029905fffc3ca6a2f6a38022584a
- Unneeded __bridge: https://github.com/mindsnacks/moai-dev/commit/3d16a64bf75d34213d9eb0328c9acb2d73d4f7ab