Checks whether to add Atmos shim or not based on Atmos supported version...

...s of Akka and Play.

Checks the supported version based on hard coded values in the Dependencies.scala file. Not the most elegant solution but it gets the job done. In order for an Atmos shim to be added it needs to fulfil all of the following criteria:
* If Akka present the version <= supported version (sbt 0.12 = Akka 2.2.1 and sbt 0.13 = Akka 2.2.1)
* If Play present version <= supported version (sbt 0.12 = Play 2.1.4 and sbt 0.13 = Play 2.2.0)
* Has Atmos enabled 

If you are okay with this solution I will create a PR for sbt-echo in 1.1.x too.