sysutils/py-crontab: Rename to python-crontab, Update to 2.4.0

- Rename the port to match the canonical/registered (PyPI/CHEESESHOP) name
- Switch from CHEESESHOP to GitLab for complete tests data
- Update the project website URL in pkg-descr
- Add LICENSE_FILE
- Add sysutils/py-cron-descriptor to RUN_DEPENDS
- Add test target

Reviewed by:	koobs
Approved by:	koobs (ports, mentor), portmgr (maintainer timeout: > 2 weeks)
Differential Revision:	https://reviews.freebsd.org/D23968

Use PY_FLAVOR for dependencies.

FLAVOR is the current port's flavor, it should not be used outside of
this scope.

Sponsored by:	Absolight

Switch all pypi.python.org WWWs to a new PyPi home pypi.org where
they now redirect to anyway. All new urls checked to return 200,
I've fixed a couple of them in the process.

Approved by:	portmgr blanket, mat

Canonicalize PyPi WWWs:
- Switch to https://
- Remove trailing slashes

Approved by:	portmgr blanket

Convert Python ports to FLAVORS.

  Ports using USE_PYTHON=distutils are now flavored.  They will
  automatically get flavors (py27, py34, py35, py36) depending on what
  versions they support.

  There is also a USE_PYTHON=flavors for ports that do not use distutils
  but need FLAVORS to be set.  A USE_PYTHON=noflavors can be set if
  using distutils but flavors are not wanted.

  A new USE_PYTHON=optsuffix that will add PYTHON_PKGNAMESUFFIX has been
  added to cope with Python ports that did not have the Python
  PKGNAMEPREFIX but are flavored.

  USES=python now also exports a PY_FLAVOR variable that contains the

Remove ${PORTSDIR}/ from dependencies, categories r, s, t, and u.

With hat:	portmgr
Sponsored by:	Absolight

Update to version 1.9.5

Sort USE_PYTHON

Module for reading and writing crontab files and accessing the system cron
automatically and simply using a direct API.

WWW: http://pypi.python.org/pypi/crontab/