cleanup: rename package and vendor dependencies for old go versions

Fixes #8 and begins to address deployability.

vendor/github.com/pebbe/zmq4/zmq4.h

@@ -0,0 +1,62 @@
+#if ZMQ_VERSION_MAJOR != 4
+
+#error "You need ZeroMQ version 4 to build this"
+
+#endif
+
+#if ZMQ_VERSION_MINOR < 1
+
+#define ZMQ_CONNECT_RID -1
+#define ZMQ_GSSAPI -1
+#define ZMQ_GSSAPI_PLAINTEXT -1
+#define ZMQ_GSSAPI_PRINCIPAL -1
+#define ZMQ_GSSAPI_SERVER -1
+#define ZMQ_GSSAPI_SERVICE_PRINCIPAL -1
+#define ZMQ_HANDSHAKE_IVL -1
+#define ZMQ_IPC_FILTER_GID -1
+#define ZMQ_IPC_FILTER_PID -1
+#define ZMQ_IPC_FILTER_UID -1
+#define ZMQ_ROUTER_HANDOVER -1
+#define ZMQ_SOCKS_PROXY -1
+#define ZMQ_THREAD_PRIORITY -1
+#define ZMQ_THREAD_SCHED_POLICY -1
+#define ZMQ_TOS -1
+#define ZMQ_XPUB_NODROP -1
+
+#endif
+
+#if ZMQ_VERSION_MINOR < 2
+
+#define ZMQ_MAX_MSGSZ -1
+
+#define ZMQ_BLOCKY -1
+#define ZMQ_XPUB_MANUAL -1
+#define ZMQ_XPUB_WELCOME_MSG -1
+#define ZMQ_STREAM_NOTIFY -1
+#define ZMQ_INVERT_MATCHING -1
+#define ZMQ_HEARTBEAT_IVL -1
+#define ZMQ_HEARTBEAT_TTL -1
+#define ZMQ_HEARTBEAT_TIMEOUT -1
+#define ZMQ_XPUB_VERBOSER -1
+#define ZMQ_CONNECT_TIMEOUT -1
+#define ZMQ_TCP_MAXRT -1
+#define ZMQ_THREAD_SAFE -1
+#define ZMQ_MULTICAST_MAXTPDU -1
+#define ZMQ_VMCI_BUFFER_SIZE -1
+#define ZMQ_VMCI_BUFFER_MIN_SIZE -1
+#define ZMQ_VMCI_BUFFER_MAX_SIZE -1
+#define ZMQ_VMCI_CONNECT_TIMEOUT -1
+#define ZMQ_USE_FD -1
+
+#define ZMQ_GROUP_MAX_LENGTH -1
+
+#define ZMQ_POLLPRI -1
+
+#endif
+
+#ifndef ZMQ_ROUTING_ID
+#define ZMQ_ROUTING_ID ZMQ_IDENTITY
+#endif
+#ifndef ZMQ_CONNECT_ROUTING_ID
+#define ZMQ_CONNECT_ROUTING_ID ZMQ_CONNECT_RID
+#endif