Add some docstrings.
Merge branch 'master' of ssh://common-lisp.net/project/asdf/public_html/asdf

Merge necessary because of local docstring addition.
Document strings for the OPERATION subclasses that handle propagation.
Merge branch 'master' of ssh://common-lisp.net/project/asdf/public_html/asdf
Second pass on docstrings previously edited by rpgoldman.
Also fix the name of the :initarg for upward-operation (oops).
Bump version to 3.1.0.38