Allow for the parallel simulation and comparison of trjs with unique initial conditions.

Updating my branch.  I know I will need to change some networkx stuff, and I think the result file compression handling has changed.  This will impact how the parallel trajectory pickles are recombined.

I also added an isothermal compressibility target a few months ago - it's useless (for now) as the needed sampling is on the order of 100 ns.
That's a good point. The other properties aren't that useful either.  You may either remove all of the unnecessary properties (which would clean things up, but probably require fixing bugs) or keep them all.