Progress bar for 'delphin process'

[goodmami]

When delphin process is run, no output is shown until it is complete, unless the -vv option is used. This option is somewhat obscure (just one -v doesn't really do anything) and easy to forget, so something like a progress bar would be more user-friendly. The progress package looks very nice, but if we don't want to incur another dependency it should be easy to make a simple progress bar.