Merge branch 'release_candidate' into 'master'

Release version 0.4.0

Closes #33 and #15

See merge request chronusq/chronusq_dev!89
4 jobs for master in 112 minutes and 52 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #4508
build_gcc

00:48:55

passed #4507
build_intel

00:46:06

passed #4523
build_mpi_gcc

01:03:55

failed #4509
build_mpi_gcc

01:05:00