CBD-380: Add ItemMetaData as member of Item class
CBD-380: Add ItemMetaData as member of Item class

Change-Id: I61db11674326197b5f66c45f0aa8346fe8558d3a
Reviewed-on: http://review.couchbase.org/17359
Reviewed-by: Chiyoung Seo <8b279095f11c26cc21045fda5a3e51debb005aa9@gmail.com>
Tested-by: Chiyoung Seo <8b279095f11c26cc21045fda5a3e51debb005aa9@gmail.com>

membase/ep-engine,abhinavdangeti/ep-engine,daverigby/ep-engine,sriganes/ep-engine,couchbase/ep-engine,couchbase/ep-engine,abhinavdangeti/ep-engine,daverigby/kv_engine,sriganes/ep-engine,abhinavdangeti/ep-engine,teligent-ru/ep-engine,sriganes/ep-engine,jimwwalker/ep-engine,daverigby/kv_engine,sriganes/ep-engine,couchbase/ep-engine,abhinavdangeti/ep-engine,abhinavdangeti/ep-engine,daverigby/ep-engine,owendCB/ep-engine,membase/ep-engine,hisundar/ep-engine,hisundar/ep-engine,jimwwalker/ep-engine,teligent-ru/ep-engine,daverigby/ep-engine,hisundar/ep-engine,jimwwalker/ep-engine,jimwwalker/ep-engine,owendCB/ep-engine,daverigby/kv_engine,daverigby/kv_engine,hisundar/ep-engine,couchbase/ep-engine,owendCB/ep-engine,membase/ep-engine,membase/ep-engine,teligent-ru/ep-engine,teligent-ru/ep-engine,owendCB/ep-engine,daverigby/ep-engine