Turns out that even distro as new as RHEL7 does not still support
python3 properly.  This commit enables fallback to python2 on older
distros.

RPM part could be solved by rpm macros; Debian part is left to require
Python 3.4 (as per current stable); we can fix that later if need be.

Overview of changes:

 *  Converted snippets to Python 3

    Be ready for Python 3; Fedora 28 already started complaining.

 *  Codebase and meta-data maintenance

Fedora 28 already issues deprecation warnings, which disrupt tests.

Overview of changes:

 *  Updated SPEC file template

    Turns out Perl is not available on all Fedora machines, so not
    having it in Requires prevented some machines from updating to
    v0.1.2.

Overview of changes:

 *  Made packaging and meta-data updates and improvements

    Mostly refactoring to make better use of MKit's features and provide
    more robust, simpler and maintainable package meta-data.

 *  Updated format of version declaration

    Format of Shellfu module version has been changed briefly after
    introduction so we have changed it to match.

 *  Fixed typo in first name

 *  Fixed test log header

 *  Added upper Shellfu version limit

 *  Updated MKit to v0.0.28

To make it a bit easier to maintain multiple Shellfu/Bash libraries, we
want to have sort of "template" and keep every module as close to it as
practical.

Replace tabs with spaces and use more logical grouping

TFKit will not see it otherwise.

Shellfu v0.10.4+ will use the newer format.  This does not justify
hard dependency change, as no known functional components rely on the
version; only thing that uses it is sfdoc to display module version in
man page footer.

No need to use package name if there is only single binary package.

Overview of changes:

 *  Added missing python dependencies
 *  Fixed Debian build time test

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

Already v0.1.0 since it's been used for ages as part of BMO (my other
project, not released yet.)