Reactive Slick

Here's the ongoing work on Reactive Slick.

/cc @cvogt for review later
You mean transform and transformWith? They look like alternative ways to do the same thing. `asTry` == `transformWith(Future(_))`, `transform(f)` == `asTry.map(f).map(_.get)`.

BTW, here's the current use of asTry for Actions:
```
      def nonFused =
        StartTransaction.andThen(a.asTry.flatMap(new EndTransaction(_))(Action.sameThreadExecutionContext))
```
where EndTransaction does the `.get` to roll the `Try` back into the resulting `Future`