Fixed exception throwing, fixed vcell cli log creation option, and fixed variable passing

[CodeByDrescher]

1. An exception was thrown to indicicate models had failed, but instead caused VCell to believe it had fatally crashed.
2. vcell batch mode improperly disregarded a flag telling it to force vcell log files. Additional features to keep flushing the logs were included.
3. "bCoerceToDistributed" was passed down from start to end as a local variable, but had no impact on most functions it passed through. It's now passed to constructers only and saved as a constant instance variable (similar to the other boolean runtime options, like bKeepLogFiles)