Add cross-compile support for Scala 2.11.1

I built a version of Scoobi from Eric's 2.11 branch. The tests all seem to work locally.

I'm assuming the biggest problem will be the blackbox macro stuff. In that it isn't backwards compatible with 2.10. I'm assuming this is what you meant by deprecated warnings Mark. :(

/cc @markhibberd @etorreborre 
This is just to share the `MacrosCompat`. Happy to add another module if that's cleaner/better.