Add ReceiveActor and MatchBuilder

Also updated PingPong to perform tests against ReceiveActor
Merge pull request #225 from HCanber/receive-builder-104

Add ReceiveActor and MatchBuilder
Created ReceiveActor and MatchBuilder.
Also updated PingPong to perform tests with ReceiveActor

Apart from changes in PingPong, nothing has changed.
Doc will come, but in the meantime, look at src/core/Akka/Util/MatchHandler/README.md