etcupdate, svnlite, documentation etc. following the transition of source to Git

[Graham Perrin]

Sorry for the mis-formatting and lost line breaks in my previous e-mail. 
Blame Thunderbird.

As reference:

<https://www.freebsd.org/cgi/man.cgi?query=hier&sektion=7>

/usr/src

 > BSD, third-party, and/or local source files