Update all Django ports to new security releases

On August 20, the Django team issued new security releases addressing
multiple vulnerabilities [1]. Update all of our Django ports accordingly:

• www/py-django: Update to 1.6.6
• www/py-django14: Update to 1.4.14
• www/py-django15: Update to 1.5.9
• www/py-django-devel: Update to 1.7 release candidate 3

While I'm here:

• Switch to USES=python and USE_PYTHON=<features>
• Deprecate OPTIONSFILE
• Add CPE information
• Add LICENSE_FILE
• Tweak HTMLDOCS option description

And for www/py-django-devel:

• Switch to GITHUB for distribution files

[1] https://www.djangoproject.com/weblog/2014/aug/20/security/

Approved by: lwhsu (maintainer)
MFH: 2014Q3
Security: 3c5579f7-294a-11e4-99f6-00e0814cab4e