Revert "Checks whether to add Echo shim or not based on Echo supported version of Akka and Play."

This reverts commit 187789eb64cf78314ebadb03beea7c9b5a83b234.
deal with null getMessage
Create atmos plugin .sbt files or not depending on akka/play version

We already never created these files for sbt 0.12 projects so we
continue that.

Build info added to integration tests so they automatically stay
in sync with the latest version we claim to support.
Merge pull request #63 from sbt/wip/havocp-port-from-1.0.x

port fixes from 1.0.x