This also touches doc and src a bit. It should be committed per book or
article, not as one big change.
This includes:
- Handbook (convert some examples about svn-ports to svn-src)
- Porters Handbook
- drop RCS IDs and SVN keywords
- modernize some sections: CURRENT is now at 14 and iconv is in all supported versions of the base system.
- the section about git status --short needs double-checking.
- Committers Guide
- drop psvn, addport, mfh, cgit-beta
- add quarterly branch name
- note that re-adding and copying a port are being investigated
- Problem Reports (lightly touched)