Remove yard doc from development dependencies

It is better to call it as standalone executable

Change-Id: Id0476db97c0faa7008d1e1f1dd3d223f7bcf11fb
Reviewed-on: http://review.couchbase.org/24478
Tested-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>