kngclick: style non-hyphenated dl terms as yellow

When styling definition-list terms, style non-hyphenated terms as yellow,
so that, in option lists, we consistently use the white-bold styling only
for command-line literals.

Signed-off-by: Gregory M. Turner <gmt@be-evil.net>
kngclick: fix command-list highlighting

My first attempt to add the new yellow-bold styling for definition-list
terms worked for Options, but broke the white-bold styling I wanted for
the Commands definition lists.

To fix this, dl_style_word needs to know what section we are in; however,
this is not preserved anywhere accessible to dl_style_word.  To fix this,
we wrap the HelpFormatter.section() contextmanager to remember the
current section title before calling the inherited implementation, and
do the yellow-bold styling only if we are in the "Options" section.

Signed-off-by: Gregory M. Turner <gmt@be-evil.net>
setup: fix the download url for git

This not used AFAIK (but I'm a PyPI ignoramus), but just in case:
if __version__ is 9999 (aka git) there is a different url
pattern we can use to get the current tip-revision tarball from
github.

Signed-off-by: Gregory M. Turner <gmt@be-evil.net>
kernelng overlay create: new uid/gid options

This adds uid/gid options when creating the overlay.  We get the default
values from portage_uid and portage_gid.

Since this creates a portage dependency, update setup.py accordingly.

Signed-off-by: Gregory M. Turner <gmt@be-evil.net>
kernelng overlay create: add --perm option

This adds a permissions option for the file permissions
of files created in the overlay.  It also adds an
OCTAL_3 click option type to accomodate this.

Includes some dummy debug output that doesn't really
belong there, but is a sensible placeholder for the moment.

Signed-off-by: Gregory M. Turner <gmt@be-evil.net>