Adaptable Service Context

Tamaya should support an adaptable ServiceContext to resolve any kind of implememntation services, both API services as core framework services. The ServiceContext should be dynamically replecable by configuring an alternate instance of using the Java *ServiceContet+.

This decouples component usage from its load and management part and als greatly simplifies integration with new/alternate runtime environments. The service context is exptected to provide

single singleton instances: these service can be cached.
access to multiple instances which implement some commons SPI interface.
as useful priorization of components is done by the model itself.