API Docs build adjustment.
For a "package" which has a main piece and submodules, the
main part is now processed before, rather than after, the submodules.
Usally there's introductory material (e.g. in the main module's
docstring) and it's more useful for this to appear at the top of
a page rather than down after all the submodules.
Made some docstring tweaks in two modules where the result didn't
look very good - Debug and PathList. For PathList, Sphinx doesn't
process both a class docstring and its __init__ method's docstring -
you get one of the other, so joined those together.
Signed-off-by: Mats Wichmann <mats@linux.com>