Minimize the "built part" and code repetition among saturnin "clones".

To allow for experimenting with functions from embedded library.

This should help test and manage embedded Fastfoo library

mkusage exits by default so it's intended to exist as one call per
process only.

If for certaiun group a mode is not specified, fall back to
a value inhertited from environment, or eventually to 644.

 *  Add docstring,
 *  add explanations for local variable names,
 *  separate export declarations,
 *  sort globals alphabetically,
 *  add built part delimiters,
 *  quote paths properly.

... turns out it's faster (surprise! ;))

Due to inigrep limitation, we cannot automatically cherry-pick hook.ini
based on where the hook is found--we can only have all hooks in one
file, or use join strategy.

Conventional ip wrapper -- not desktop-related.

A debugging utility -- not desktop-related.

Conventional curl wrapper -- not desktop-related.

Conventional rsync wrapper -- not desktop-related.

Conventional virsh wrapper -- not desktop-related.

Add section like this to hook.ini:

    [hook.mycomm]
        pre = echo $SATURNIN_SUBCOMMAND will run soon
        pre = echo $SATURNIN_SUBCOMMAND is almost running
        post = echo $SATURNIN_SUBCOMMAND has finished now

"@" breaks the string to several arguments, which is not what we want
here

An improved version of previous code

Better left to init system or desktop manager or hooks