Fix off-by-one bug reported on lammps-users

This fixes an off-by-one bug in the atom type validation check. Closes #91.
It also enables type and style hints by default and replaces
the -charmm command line flag with -nohints flag (to turn them off).
Hints are also added to section headers.
Add a brief minimization to example input template.
Step patch level version to 1.8.3.