Added the capability to copy a MiniSat solver.
More work on checkpointing MiniSat.

Still doesn't work.
Fixed copying of MiniSat solver.
Removed debug prints from MiniSat.
Remove debugging info from minisat.
Expose status checkpointing to NativeSolver implementors.
Populate random_seed for new MiniSat solvers.
Random seed must be positive.
Checking to see if the random seeds are causing problems.