Add example projects

We should provide example projects with various implementations, including:

- Basic Example
- [MagicalRecord](https://github.com/magicalpanda/MagicalRecord)
- [ObjectiveRecord](https://github.com/mneorr/ObjectiveRecord)

Other potential implementations:

- [SSDataKit](https://github.com/soffes/SSDataKit)?
- [mogenerator](https://github.com/rentzsch/mogenerator)?