www/node: 6.0.0 -> 6.1.0

Update to the latest upstream v6.x current release after the recent
openssl CVEs. This release also includes several semver minor changes.

Release announcment with changelog is here:

https://nodejs.org/en/blog/release/v6.1.0/
https://nodejs.org/en/blog/vulnerability/openssl-may-2016/

PR: 209342
Submitted by: Bradley T. Hughes <bradleythughes@fastmail.fm> (maintainer)