Powerargs

Refactored the Event Store Options for easier maintenance of the options.
1. The Event Store Options are now just plain pocos.
2. Their default values are now set in the constructor.
3. Their command line descriptions are now set via attributes. 
    a. Currently via PowerArgs ArgDescription but can easily be converted to an EventStoreArgumentDescription Attribute if we don't want to pollute the EventStore assemblies with PowerArgs