Consistent LAMMPS header comments and URL fixes

[akohlmey]

Summary

This PR adds missing LAMMPS comment header to files in the src/ tree where missing, updates the homepage URL, flags them as C++ and applies a few more similar fixes.

Author(s)

Axel Kohlmeyer, Temple U

Licensing

By submitting this pull request, I agree, that my contribution will be included in LAMMPS and redistributed under either the GNU General Public License version 2 (GPL v2) or the GNU Lesser General Public License version 2.1 (LGPL v2.1).

Backward Compatibility

Yes. only comments are changed.

Post Submission Checklist

• The feature or features in this pull request is complete
• Licensing information is complete
• Corresponding author information is complete
• The source code follows the LAMMPS formatting guidelines
• The feature has been verified to work with the conventional build system
• The feature has been verified to work with the CMake based build system

[athomps]

I accept, although it is not clear that the change from http to https is necessary, since both work, even from Sandia network.

[akohlmey]

I accept, although it is not clear that the change from http to https is necessary, since both work, even from Sandia network.

The main reason is to have everything (more) consistent, so that when we have the need to make changes (e.g. to the LAMMPS home page URL), they can be automated. Also some files were missing the LAMMPS comment entirely (which is required to apply the GPL).

Mind you, many current web browsers will switch automatically from http:// to https:// if the latter is available, some web browsers are encouraging using an https:// only mode and will print increasingly serious warnings about "unsafe" connections if you don't have/use https://. So it is just a matter of time until this change will be required.

[sjplimp]

alll good