cross-build for scala-2.10 and scala-2.11, updated dependencies

First attempt at scala-2.11 compatibilty.
It compiles, tests and works
Spray currently publishes only a nightly with 2.11 support, so there is a need for special handling of spray dependency.

Another breaking change is update of scala-logging to its successor - that causes some changes in mixed traits.

Final changes are those required by scala itself - in 2.11 case classes without parameter lists are forbidden

If this PR is merged, I think it should be a version bump due to incompatility with previous scalalogging.