ORM to Slick Draft, needs polishing

review by @szeiger 

Please already review this. I keep polishing it as we go a long.
> There is something along these lines called `MappedTo`

Yes, but value classes can not inherit from traits (since traits inherit from `AnyRef`), so the following fails:

```
scala> case class Latitude(value: Double) extends AnyVal with MappedTo[Double]
<console>:8: error: illegal inheritance; superclass AnyVal
 is not a subclass of the superclass Object
 of the mixin trait MappedTo
       case class Latitude(value: Double) extends AnyVal with MappedTo[Double]
                                                              ^
```