This reverts commit 950d1fd9.

Well, that ended quickly and badly...

Per the "Practical Python Porting"

The error:
    AttributeError: 'dict_keys' object has no attribute 'sort'

A build time option to disable all dangerous operations that
ntpq can produce isn't possible.  We'll just have to do security right
in ntpd itself.

Use correct variable name for user input
Fix copy-pasta from do_addvars

If the path points to a link, not a file, ntpviz tried to overwrite
the link, and failed with error.

Splitting the same 1MB file over and over again the same way is
very inefficient.  So cache it.

It might be good to just peersplit once when peerstats loaded.

...under tests/perl might have reatained some usefulness as models for
tests of the Python utilities. In practice, after looking at it,
probably not. It will remain in the repository history before
this commit, in any case.

A convenience method for fetching the host's system variables.

Next up is likely putting all the autoscale/percentages in a
single function

This simplifies the notation, but stuip %-substition does not work
with dictionaries.

namedtuples have a baffling restriction of 4 elements, so unuseable.

I run 8 copies of ntpviz, now I can tell them apart.

Now ntpviz buffers up the new index.html, and writes it all at
the end.  Serving up blank files confuses users and browser reloads.