Substantial changes to VesselSimulator

As reported in the thread, I think I've got my changes to the simulation code working properly.  This includes the following:
Simulation algorithm now explicitly uses Kasuha's fuel flow rules and should be much easier to understand.
Copies all data required by the background thread into KER's data structures so that no attempt is made to access any core game data that may change while the background simulation is running.
Added lots of logging mostly controlled by LOG conditional flag in the new Logging build configuration (though lots of extra logging is commented out).
Adding logging to various exception handlers and added exception handling to more places.
Removed lots of uses of "this."