Add support added for LICENSE=NONE, use it when the port doesn't
have cleanly defined licensing terms. Note that without clean
license allowing you to use and distribute the code it would be be
illegal to do so in many jurisdictions, so for ports with NONE
license no distfiles or packages are distributed.

While here, fix trailing whitespace in CHANGES.

Approved by: portmgr (bapt)
Differential Revision: D7816