Design: Make different simulation specializations combinable

[Christoph Thiede]

The introduction of SimulationContext was important to facilitate the creation of custom context classes. Nevertheless, it's a shame that at the moment, you have to decide on one concrete subclass of SimulationContext. For example, you cannot combine the functionalities of SimulationMsrContext and SandboxContext. For further possible conflicts, refer to #14. It would be great to eliminate this limitation.

Possible approaches:

• Composition (e.g. a subclass of SimulationContext, PluggableContext, defines hook and forwards them to a Simulator instance)
• Chain of Responsibility vs list of simulator objects to be invoked in series ("explicit CoR")

Keep performance in mind (see #13)!