Add initial support for cmake

Change-Id: Idc7482bab1d2aea9fd57b798b18cc7833138c0ee
Reviewed-on: http://review.couchbase.org/26927
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>