validation.

instead of any other monkey business (this is simpler and safer).
We'll also increment the user's login counter on success, for now.

Contents of components/header.xjs (if exists) appear under
navbar and above page content.
Contents of components/footer.xjs (if exists) appear
at bottom of page (in a <footer/> block).
You can use this to add a banner/image to the top of your
pages, or include some server or client-side JS that runs on
every page load (without having to modify index.xjs).

Use get/post as appropriate.
Light housekeeping; hopefully this script won't live much longer.

Feed post and get requests into a common function, which will
become useful later.
Starting to use ES6 stuff in client-side scripts with greater
abandon.  May not work with your ancient browser. #wontfix

For txt sidebar modules, avoid outputting <pre> tags unless the
file gots some stuff in it.

Get last callers with negative index for most recent calls.

Use last_few_callers setting of above to determine how many records
to display.
Reverse the order of the list; for whatever reason, that looks
better to me right now.

sidebar module.

Since you don't "call" a website, we'll just call this a "recent
visitors" list.
Visitation may occur via H.T.T.P. or T.E.L.N.E.T. etc.

If user is logging in (sent credentials and successfully authed),
destroy their existing session store (if any) to treat this as a
new login.

This is updated on new logins, or after settings.timeout expires.
(This will also be the place to update the recent-logins list.)

Get angry if someone's alias or realname doesn't pass system.check_name(). Stop people named Phil from doing the sorts of things that Phils do.