Improvements to GROMACS tools

pdb2gmx writes total charge differently

pdb2gmx notes the total charge for each residue in the [atoms] field of the topology file it produces. The fact that this should generally be an integer can be used for troubleshooting issues in system or force field preparation. This printing is now done only once per residue, rather than for every atom.

nmeig does thermochemistry

The nmeig tool that analyzes the Hessian matrix from a normal mode analysis now generates thermochemical properties like standard entropy, heat capacity at constant volume, internal thermal energy and zero-point energy. The analysis is based on the harmonic approximation that is the same as what is used in quantum chemistry.

Implement writing of LaTeX methods in report-methods

Added a new tool report-methods to write a summary of methods used to set up a simulation to an output file or to standard output.