Use recursive CMakeLists.txt

Change-Id: I9ed21b4d5b75ed57521e9cdb69b25abcdd1e9364
Build libconflate with cmake

Change-Id: I4a04ac5294a887a98a67cbb8184a325b4e55839c
Build memcached with cmake

Change-Id: I1d2809ff8c0c8440a6ed79a1f8915880af3acf09
Try to build libevent as well

Change-Id: Id0f8d57f77181eafb98fc73cd1da84a14c2756bd