Added missing touchMulti V8 binding.

Change-Id: I3e7e5268ec1f1c3da3f6ba3d87e1da3a85a85e86
Reviewed-on: http://review.couchbase.org/29395
Tested-by: Brett Lawson <brett19@gmail.com>
Reviewed-by: Mark Nunberg <mnunberg@haskalah.org>