Package cleanup: every file in asdf itself now :use's asdf/driver asdf/upgrade.
Test script fix:
Allegro, like ECL *really* hates that we close *standard-input*,
so stop trying at all.
Tweak some utilities and debug utilities.

On Allegro, frob the autoload earlier and intern the gethostname later
so we don't unnecessarily autoload stuff.

On CLISP, don't undefine functions, just unintern everything in the beginning,
and it won't complain about disappearing methods anymore.

Also, only retrigger the upgrade attempt on source-registry change
if ASDF was not upgraded yet. This avoids unnecessary reloading of ASDF.

Finally, be sure to share more symbols between everyone - hopefully,
all the symbols that were used in ASDF and got recycled.
Slot names are a big one, notably.

Export more ASDF internals in various packages,
that they may be shared with ASDF/INTERFACE without causing fishiness.
Be less prompt to nuke symbols that may clash.
There are plenty of innocent symbols such as O and C, etc.

Also, disable most of test-encodings when there is no asdf-encodings.

Much cleanup in image support and hooks.
More package hacking.
New feature for :version: `(:read-file-from ,path) - thanks to Stelian Ionescu.
The driver now homesteads the package nickname d.
Rename-package it away if you don't like it.

Package tweaks to make CLISP complain less.
run-program/ and run-shell-command fixes and test updates.
wildening fix to issue found by CLISP.
! is used by EXT on CLISP, so use !p for defparameter.
More pathname madness for allegro.
Better upgrade.

This notably includes the former xcvb-driver:run-program/,
a much better replacement for run-shell-command.
This also includes image initialization, dumping, quitting.

TODO: Create a define-package that can make it upgrade itself.