Patch release 8 February 2019

# Conflicts:
#	.github/PULL_REQUEST_TEMPLATE.md

Add Kokkos version of angle/cosine

Update Kokkos library to v2.8.00

Collected small fixes for the next patch release

New GitHub PR templates

Add a code of conduct to lammps github project

complete the "github open source best practices" setup by adapting a
code of conduct for any public communications about LAMMPS on github.

add readme file adapted from https://github.com/pmla/polyhedral-template-matching/blob/master/README.md to USER-PTM package

Rename python.h to lmppython.h

Update issue templates to have a different template for bug reports and feature requests.

Take advantage of the fact, that GitHub now allows to have separate issue templates for bug reports and feature requests

Patch release 1 February 2019

Correct calls to atom->delete_callback()

Use argparse module in for Install.py scripts in lib and further portability and consistency enhancements. Some lint removal as well.