Fork memory

[LinqLover]

Create a copy of the memory at a certain time index. The copy can be continued independently of the original memory.

[LinqLover]

This needs further discussion: What exactly should be copied? One option would be an eager copy of the process, which could be shallow (including side effects on the original process) or deep (very expensive). Another option would be a lazy copy via something like SimulationStudio's Sandbox, which would be slower and have unclear proceed semantics. In the latter case, there would also be an engineering issue to find out whether tracing simulators and sandbox simulators can be plugged together as simply as the Simulator CoR is designed (see #68).