Merge branch 'fix_license' into 'master'

Update license to GPL

Closes #250

See merge request !115
5 jobs for master in 15 minutes and 18 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
passed #181381
docker
build_linux_36

00:05:23

passed #181382
docker
build_linux_37

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passed #181379
macosx
build_macosx_36

00:14:22

passed #181380
macosx
build_macosx_37

00:13:58

 
  Deploy
passed #181383
docker
deploy_beta

00:00:56