Bunch of work on pushing and replication of tags and capabilities, and protocol cleanup.

node/Capability.hpp

@@ -109,6 +109,11 @@ public:
 	 */
 	inline uint64_t networkId() const { return _nwid; }
 
+	/**
+	 * @return Expiration time relative to network config timestamp
+	 */
+	inline uint64_t expiration() const { return _expiration; }
+
 	/**
 	 * Sign this capability and add signature to its chain of custody
 	 *