documentation: Added February 2013 as release date for 1.3.1
I added this date as the release date for the five manuals
that have a manual history table.
(From yocto-docs rev: 5f107aab8bd2de0be78163eaf356656ddae4bf5f)
Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>