Add some USB gadget example drivers for USB audio, USB keyboard,
USB mouse and USB modem classes. Hopefully someone will find
these examples useful when implementing USB device side drivers
using the FreeBSD USB stack.
Sync-up with bsdinstall(8) FTP mirrorselect changes.

SVN r224656:
Add back ftp4, a new machine has taken its place. ftp2 and ftp8 are both
IPv6 capable mirrors.  cvsup4/ftp4 have already been added to the handbook.

NOTE: Except put IPv6 entries in IPv6 section at the top of the list

SVN r225467:
Add ftp4.se.freebsd.org to the IPv4 and IPv6 mirror lists.

SVN r235228:
Add the IPv6 tag to ftp4.fr.freebsd.org.

NOTE: Except dup entry into IPv6 section.

SVN r243832:
- Remove snapshots.se.freebsd.org [1]
- Add ftp6.se.freebsd.org

SVN r243854:
Remove snapshots.jp.freebsd.org. It stopped working years ago.

SVN r253543:
Update mirror list to more closely match
http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/mirrors-ftp.html

MFC after:	1 week
Fix build.