Issue 10: add more configuration files by default

It can be convenient to be able to customize localization settings
when creating an image (clock, keyboard, language, timezone).

This commit introduces the command line options and the code to
do so, along with some sane default settings.

Signed-off-by: Rune Morling <ermo@foresightlinux.org>
Write more configuration files so that less modification is required in
the final image.  Some changes to Rune's work for consistency.

Signed-off-by: Michael K Johnson <johnsonm@foresightlinux.org>

Fixes #10
Merge branch 'configfiles'