Add TTL options to memory registry.

registry/proto/registry.proto

@@ -17,6 +17,7 @@ message Service {
 	map<string,string> metadata = 3;
 	repeated Endpoint endpoints = 4;
 	repeated Node nodes = 5;
+        Options options = 6;
 }
 
 // Node represents the node the service is on
@@ -42,6 +43,11 @@ message Value {
 	repeated Value values = 3;
 }
 
+// Options are registry options
+message Options {
+        int64 ttl = 1;
+}
+
 // Result is returns by the watcher
 message Result {
 	string action = 1; // create, update, delete