Bug #4: Fix for comparison function application

A comparison function was passed to some functions. But it was not called.

This implementation detail was also acknowledged by Frédéric Bour.
https://sympa.inria.fr/sympa/arc/caml-list/2014-09/msg00127.html

The function which was passed by the parameter "cmp" should be called
in the affected modules "Omap" and "Oset" now.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Bug #5: Explicit dependency on "OCaml" for the installation package

Data formats for software packages can contain specifications which should
express dependencies between software components. A corresponding OCaml
version constraint was added for the package formats "DEB" and "RPM".

See also:
http://www.math.nagoya-u.ac.jp/~garrigue/soft/olabl/classes/#distribution

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Merge adjustments into "next"

* Bug #4: Fix for comparison function application
* Bug #5: Explicit dependency on "OCaml" for the installation package
Another software release (Bugs #4 and #5)

* Bug #4: Fix for comparison function application
* Bug #5: Explicit dependency on "OCaml" for the installation package