Added ASDF_DEVEL_SOURCE_REGISTRY.

This will give the ASDF developer a special way of initializing the ASDF
source registry to load the libraries needed to run Faré's builder tools.
Merge branch 'master' of ssh://common-lisp.net/project/asdf/public_html/asdf
Merge branch 'master' of ssh://common-lisp.net/project/asdf/public_html/asdf
Check exit status in a RUN-SHELL-COMMAND test with verbose set.
Merge branch 'master' of ssh://common-lisp.net/project/asdf/public_html/asdf
Merge branch 'master' of ssh://common-lisp.net/project/asdf/public_html/asdf
Quiet a style warning.

In ENOUGH-NAMESTRINGS, the variable B was bound to a value computed only
for side-effect.  Removed B, lifting the call to ENSURE-PATHNAME out of
the LOOP form.
Merge branch 'master' of ssh://common-lisp.net/project/asdf/public_html/asdf
Merge branch 'master' of ssh://common-lisp.net/project/asdf/public_html/asdf
Fixed bug in source registry configuration.
Prepare for 3.0.2 release.