Libevent client conflicts with C client

Aerospike Libevent client installs 3 header files with same name as C client - citrusleaf/cf_atomic.h, citrusleaf/cf_clock.h and citrusleaf/cf_queue.h . So, it is impossible to have both developer client libraries installed on same box.

Suggest to move listed files to citrusleaf_event2 directory (proposed patch).