Use recursive CMakeLists.txt

Change-Id: Idd0d390fda3864565e6590d549344138d0471eff
Reviewed-on: http://review.couchbase.org/28726
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>