Updated Akka to 2.3.0, not thoroughly tested

Hello there!

It seems as if flow does not work correctly on Akka 2.3.0 without being recompiled against this version. 
This change ups the akka-actor dependency version to 2.3.0 as well as the project version to 1.2.0. 

I have not yet tested this thoroughly, but it seems to be working correctly.
I will report back if I notice anything that's off!