graphics/py-png: update 0.0.13 -> 0.0.17

- Change MASTER_SITES
- Add LICENSE
- Change WWW

PR:		194220
Submitted by:	Zhihao Yuan <lichray@gmail.com>
Approved by:	mentors (implicit)


git-svn-id: svn+ssh://svn.freebsd.org/ports/head@372181 35697150-7ecd-e111-bb59-0022644237b5
Deprecate.

Sponsored by:	Absolight


git-svn-id: svn+ssh://svn.freebsd.org/ports/head@372182 35697150-7ecd-e111-bb59-0022644237b5