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

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

Whitespace nit

Use REQUIRE: line to reorder rc.d/bridge instead of BEFORE: line.

Pointed out by: dougb
Approved by: re (bz)

Fix the script order to run rc.d/bridge after the initial network
interface configuration and before running network daemons.

Approved by: re (kib)

Remove trailing white space. No functional changes.

As previously discussed, add the svn:executable property to all scripts

Eliminate global symbols starting with an underscore from rc.d
scripts, except for mdconfig* and jail. Such symbols are reserved
for the rc.subr internals. Most scripts can be fixed by just
declaring _foo symbols as local: few scripts actually need them to
be global.

Discussed with: dougb in freebsd-rc

Add rc.d/bridge which is invoked when a new interface arrives and can
automaticly add it to an Ethernet bridge. This is intended for applications
such as qemu, vmware, openvpn, ... which open tap interfaces and need them
bridged with the hosts network adapter, the user can set up a glob for
interfaces to be automatically added (eg tap*).