2.26.86: bin/bump-version is now written in Lisp using ASDF support functions

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.
2.26.87: use read-from-string, not eval-input, for ensure-function, as in the good/bad old days.

Also, improve the bump-version script.
2.26.88: make :read-file-from path relative to system pathname not component.

Should make fe[nl]ix happy.
2.26.89: Be nicer with :read-file-form versions. Don't consider equal inherited symbols fishy.

Also settle on names for resume-image API.
2.26.90: fix a missing package use, plus various pathname tweaks.
2.26.91: Package adjustments.

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.
2.26.92: export some slot names for enhanced compatibility.
2.26.93: play nicer with packages, notably for Allegro and CLISP

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.
2.26.94: Yet another package cleanup. Debug the test scripts.

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.
2.26.95: more frobbing of the runtime support

Settle on "restore-image" and "dump-image" for our API names.
Unbreak match-condition-p and move it to utility,
give static scoping to the generic muffler,
rename the compiler and loader mufflers.
Fix with-input.
Remove crud from script-support.
Distinguish *quit-when-done* from *debug-asdf* in script-support.
2.26.96: one more package tweak to compile cleanly.
2.26.97: more portability fixes for ECL, CMUCL, GCL, XCL.
2.26.98: more portability fixes for GCL.
Actually commit the version bump. Also, update the upgrade tests for CLISP.
Frob tests
2.26.99: portability fixes for ABCL and CLISP.
2.26.100: checkpointing a lot of progress.

* Pathname support has been cleaned up, yet again,
 extending and renaming COERCE-PATHNAME into PARSE-UNIX-NAMESTRING,
 also ENSURE-PATHNAME, many docstrings, and plenty of small enhancements.
* Bundles were refactored to take advantage of the new, more sensible,
 component-depends-on semantics.
* Image support was cleaned up again, and program-op was implemented
 to produce a standalone executable on supported platforms;
 a working hello-world-example is included amongst tests.
* The *compile-file-function* indirection was removed, with the
 ECL and MKCL object file support
 being folded into compile-file* instead.
* systems now can have NIL as component-pathname,
 instead of providing a non-sensible bogus pathname
 when no sensible pathname was determined.
 Most of our pathname functions have sensible default behavior
 when provided NIL instead of a pathname as an argument.
Add two dummy test static files now needed to hush some test warnings.