updated license information

- added COPYING file with GPLv2 text
- distribute COPYING everywhere
6 jobs for license in 3 minutes and 44 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Build
passed #159477
build:debian:jessie

00:03:20

passed #159478
build:debian:stretch

00:01:32

passed #159476
build:el7

00:01:04

passed #159475
build:tarball

00:00:28

 
  Test
passed #159479
test:python2.7

00:00:21

passed #159480
test:python3.6

00:00:23