Bump version

Overview of changes:

 *  Added --saturnin-get-subcommands devel key

    In last update I inanely removed _ls_sc sub-command used by
    completion example in saturnin-demo.  This is a final replacement,
    which is actually consistent with the rest of plumbing commands.

 *  Improved docstrings for sfdoc

    Added and fixed some old docstrings as well as added module
    docstring.

 *  Improved usage errors with newer Shellfu's pretty.sh interface

    pretty.sh in newer Shellfu can handle usage messages in more
    user-friendly way, by providing option to append error reason
    to the message itself.

    (With previous version, one could achieve similar effect but with
    more negative effect on readability.)

 *  Fixed build-time test for Debian

    Turns out that dehbelper does not install the package on its own so
    we have to deal with it manually.

 *  Minor code cleanup

mkit.ini

 [project]
-    version     = 0.4.6
+    version     = 0.4.7
     codename    = DoktorV
     name        = Saturnin
     tagline     = Spirit of your toolbox