MB-1638 Tap.py doesn't exit gracefully
MB-1638 Tap.py doesn't exit gracefully

Added a signal handler for sigint. When a user Ctrl-C's there
is no longer a stack trace. In it's place we print a line that
says that the stream was killed by the user.

Change-Id: I4f31f838224d10ea6900fdddfdfd3651664bd04f
Reviewed-on: http://review.membase.org/6119
Tested-by: Michael Wiederhold <a17fed27eaa842282862ff7c1b9c8395a26ac320@membase.com>
Reviewed-by: Chiyoung Seo <8b279095f11c26cc21045fda5a3e51debb005aa9@gmail.com>

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