Reference implementation of new ports

[Pavel Timofeev]

Hello!
FreeBSD's ports are going now to the new "staged and optionNGed world".
Of course, freebsd porters pages have to be updated.

But, I'd like suggest something more easy, for the first glance.
Let's define a couple of ports about which we can say "Yes, this port
is an example of reference implementation of our new stage+optionNG
features. This is how things must look!".
Let's support it as best practice of creating new or converting exiting ports.
I think it would really help for other maintainers as example!
These ports must contain example of that rules which was mentioned in
https://wiki.freebsd.org/ports/StageDir.
What do you think?

P.S. For some time, good place to mention about it is
https://wiki.freebsd.org/ports/StageDir. Something like "For example,
look at ports path/port and path/port"