Improve description of CLI usage as a client
Extend scope of introductory sentence for the CLI
Removing final ref to logging in as root
merge dev_4_4 -D org -I include -E exclude: PR 571 (Document latest OMERO.matlab functions (rebased onto dev_4_4))
merge dev_4_4 -D org -I include -E exclude: PR 587 (Improve description of CLI usage as a client (rebased onto dev_4_4))
merge dev_4_4 -D org -I include -E exclude: PR 588 (Removing final ref to logging in as root)