new src/ tool

Hi - we released a src/ tool today,
which allows one-line builds of LAMMPS with a variety of options:

package install/uninstall

build of auxiliary package libs

changed Makefile.machine settings for compiler, MPI, FFT, JPG, PNG

auto-added Makefile.machine settings for include accelerator packages

The old ways of doing these steps (more manually) still work. The
point of is just to make it easier.

Along with this we restructured the src/MAKE dir and deleted some obsolete

Makefile.machine files. All the other Makefile.machine files are still there,
just now in sub-directories.

The hope is that any reasonable LAMMPS build can now be done
as a one-liner with (and the line saved to a file if you like).

See examples of using it in the README files in these dirs:
bench, examples, examples/accelerate


although i have not tried it yet, i think i speak for a number of people when i say this is a
very good addition to lammps, in the spirit of simplifying the building steps.

keep up this good work, thanks!