Add the parameter/RTF files back for the examples. Put a note in
simulateCharmm.py to use the latest force fields. This is what CHARMM does for
their own tutorials, so this is fine.
Fix the following error:

Traceback (most recent call last):
  File "/path/to/python/tests/TestCharmmFiles.py", line 91, in test_HydrogenMass
    topology = self.psf_v.topology
  File "/path/to/lib/python2.7/site-packages/simtk/openmm/app/charmmpsffile.py", line 782, in topology
    topology.addAtom(atom.name, elem, residue)
UnboundLocalError: local variable 'elem' referenced before assignment
Add the copyright and license/distribution info to the top of each new file.