Remove expired ports:
2015-10-01 www/py-django16: End of extended support: April 1, 2015
www/py-django16-tastypie: Uses expired Django version
2017-04-01 www/py-django-pipeline13: Depends on expired www/py-django16, and
expired upstream
2017-04-19 www/py-djblets: Does not build with py-django18 see pr: 216758
2017-04-19 security/py-crits: Does not build with py-django18 see pr: 216758
www/py-cactus: Depends on expired Django version
devel/py-django16-tastypie-mongoengine: Uses expired Django version

Remove ${PORTSDIR}/ from dependencies, categories d, e, f, and g.

With hat:	portmgr
Sponsored by:	Absolight

security/py-crits must use django v1.6 and will not work with v1.8
Two dependencies bring in www/py-django so I have created two new slave ports
which
use www/py-django16

* devel/py-django-tastypie-mongoengine allowed you to select django 1.6 or 1.8
in the options It now uses only 1.8
* add slave port devel/py-django16-tastypie-mongoengine which uses django 1.6
* www/py-django-tastypie now sets RUN_DEPENDS only if not already set
* add slave www/py-django16-tastypie which uses django 1.6

Approved by:            mat (mentor)
Differential Revision:  https://reviews.freebsd.org/D2913