Casc 200 rebasefail

This pull request works on CASC-200.  Please ignore the previous pull request (I'll close it) as I accidentally re-based a remote branch which you cannot do and in the process made additional changes :-(

This introduces a few things:
1. Configuration strategies
2. Configuration keys
3. a simple Protocol enum to separate protocol stuff from configuration

I realized there are a few javadocs I need to fix.
Just thinking out loud, that it may be better to group keys by protocol as well. There are those that impact the client, and those that are relevant for a given protocol. Maybe we could somehow control that.