two generic methods out and xyzout are implemented.
out will write the atomic crds using the PDB format. It is defined as follows:
out(self, outName = "", chainId = "", hetSkip = 0, fmode = "w", verbose = 0)
the chainId and hetSkip parameters are currently not used.
The corresponding function xyzout is similar to out, except that it will write the coordinates only (x y z for each atom).