Merge branch 'travis' into 'ducc0'

Add support for Travis CI

See merge request !26
4 jobs for ducc0_0_3_0 in 14 minutes and 9 seconds (queued for 3 seconds)
latest
Status Job ID Name Coverage
  Build Docker
passed #1142765
build_docker

00:00:22

 
  Testing
passed #1142767
test_clang

00:12:47

passed #1142766
test_gcc

00:13:31

 
  Build Tarballs
passed #1142768
release

00:00:15