How Xchars does messages

The next version will have the Xchars running in its own thread.

The command Xchars means start the screen and put message right here, on the args list.  The intended user, me, will just pick them up with whatever module that needs them, like the console loop. We can add a mutex t parts of args list, but that is up to the individual modules.

So, Xchars becomes simple, draw the screen when asked, keep the stack of strings, and otherwise, send filtered messages back onto args list.  This is like and additional 5 lines of code. It is the power of having a common args list, use it everywhere.