new patch release

Hi all - there was a new 2Jun2020 patch release
of LAMMPS this week which includes a refactoring
of the way code for new atom styles is written. The goal
was to make it much easier for a user to add a new atom
style to the code. It also removes any performance
penalty for defining hybrid atom styles which
now essentially concatenate sets of per-atom
properties from different styles.

In the new version, to setup a new
atom style, you don’t have to write
a long list of methods that perform communication
and I/O using the per-atom data you define.
Rather you just define strings that list the
per-atom variable names you want to have
operated on by each method, and add any new
ones to places in atom.cpp/h marked with
a “customize” comment.

The details are in the Modify_atom.html doc page:
https://lammps.sandia.gov/doc/Modify_atom.html

This also means that if you already have a customized version
of LAMMPS that defines your own atom styles,
there may be some clashes with the new refactoring.

Likewise, there are some new utility functions and
classes that read potential files and format some kinds
of output. That may also break your customized code
(i.e. code not distrubuted with LAMMPS) in ways
that are hopefully simple to fix.

Thanks. And everyone out there in the worldwide
LAMMPS user community, please stay safe in these
troubled times!

Steve