Program closes when the energy of the molecular system gets too high

[rhoslynroebuck]

This issue can be replicated with the nanotube + methane simulation: the program closes when pulling the methane through the nanotube with a high force scaling.

[jbarnoud]

In the python server, we check for OpenMM exceptions while running the simulation and reset when such an exception is raised. We should do the same thing here, which requires #2.

In the meantime, we can probably reduce the issue by:

• enforcing a maximum force by default
• set a maximum total energy that would trigger a reset (which would also resolve #100)