Move plot generation code into beat.cmdline
This ties in with beat.cmdline#16 (closed): moving the plotting code there will let users of beat.cmdline/beat.editor use the same plot generation functionality as found in beat.web.
This ties in with beat.cmdline#16 (closed): moving the plotting code there will let users of beat.cmdline/beat.editor use the same plot generation functionality as found in beat.web.