Merge branch 'tweak_demos' into 'master'

cosmetics and adjustments

See merge request !182
6 jobs for master in 32 minutes and 40 seconds (queued for 1 second)
Status Name Job ID Coverage
  Test
passed test_min #246591

00:04:24

passed test_mpi #246592

00:06:58

passed test_mpi_fftw #246593

00:07:21

passed test_mpi_fftw_hdf5 #246599

00:18:16

64.0%
failed test_mpi_fftw_hdf5 #246594

00:06:39

 
  Release
passed release_image_master #246595

00:06:08