- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Fix a bug in HTTP checking/fetching.
Fix a bug in HTTP checking/fetching. Add Main Site to HTTP menu. Add new
example script browse_packages_http.sh and move existing example script
browse_packages.sh -> browse_packages_ftp.sh

Reviewed by: gjb, brd
Approved by: re (gjb), clusteradm (brd)
MFC after: 3 days

Remove unnecessary mediaClose (FTP operations are done with either ftp(1)
or fetch(1), neither of which are stateful, compared to how sysinstall(8)
did FTP operations, maintaining an open session until mediaClose).

Long URLs don't always appear even with autosizing and other tricks. So,
add some whitespace to put the URL on a line by itself, maximizing view.

Change default FTP server (s/ftp-archive/ftp/).

Add example shell script for creating a local INDEX file that can be
accessed quickly for browsing a list of available packages.