Continued work on Chain Messages, 45% front-end

Trying to neaten up the flow and make it as intuitive as possible, which
is proving to be quite a challenge. Anyway, front end is almost done,
just have to polish up a couple of things and then work out how to
package it for the server side.

After that I'll need to know how to process and save the message, then
send it back to the other clients and have it render properly.

Pretty good learning exercise, even just in the sense of how to package
up something fairly complex into a neat little parcel on both the client
and server side.