Update ubuntu ppa install docs

up-to-date with the current version of LAMMPS by simply updating your

operating system.

To install the appropriate personal-package archive (PPA), do the

To install the appropriate personal-package archives (PPAs), do the

following once:

.. code-block:: bash

   $ sudo add-apt-repository ppa:gladky-anton/lammps

   $ sudo add-apt-repository ppa:openkim/latest

   $ sudo apt-get update

To install LAMMPS do the following once:

/usr/share/doc/lammps-daily-doc/doc and example problems in

/usr/share/doc/lammps-doc/examples.

Note that you may still wish to download the tarball to get potential

files and auxiliary tools.

To get a copy of the current potentials files

To un-install LAMMPS, do the following:

.. code-block:: bash

   $ sudo apt-get remove lammps-daily

   $ sudo apt-get install lammps-daily-data

which will download the potentials files in

/usr/share/lammps-daily/potentials.

The LAMMPS binary is built with the :ref:`KIM package <kim>` which

results in the above command also installing the `kim-api` binaries when LAMMPS

is installed.  In order to use potentials from `openkim.org <openkim_>`_, you

can install the `openkim-models` package

.. code-block:: bash

Note that the lammps-daily executable is built with the following

sequence of make commands, as if you had done the same with the

unpacked tarball files in the src directory:

   $ sudo apt-get install openkim-models

To un-install LAMMPS, do the following:

.. code-block:: bash

    $ make yes-all

    $ make no-lib

    $ make mpi

   $ sudo apt-get remove lammps-daily

Thus it builds with FFTW3 and OpenMPI.

Please use "lmp_daily -help" to see which compilation options, packages,

and styles are included in the binary.

Thanks to Anton Gladky (gladky.anton at gmail.com) for setting up this

Ubuntu package capability.