Log Message:
pkgtools/url2pkg: update to 19.3.1

Changes since 19.3.0:

* Added an alternative url2pkg implementation in Python that will
  eventually replace the Perl implementation. Reasons are:

  * Perl is cumbersome to type with all the special characters
  * Perl does not even have a Boolean type, after all the years
  * Perl cannot check the number of arguments passed to subs
  * Python does not suffer from the above limitations
  * Python is available on as many platforms as Perl

* The two implementations will be kept in sync until all the features
  have made it into the Python implementation, and everything has
  automatic tests.

* Added the -v or --verbose command line option.