Update spray-json.
Update scalatest.
Update to Scala 2.10.

Knock-on updates:
- scala-io-core 0.4.2
- scala-io-file 0.4.2
- akka 2.0.5
- spray-can 1.1-M7

Use futures instead of actors in GUI Main.
Update to Akka 2.1.1.
Fix NullSpell case object extending case class Spell.
Fix creation of ClientService actor.