cleanup: rename package and vendor dependencies for old go versions

Fixes #8 and begins to address deployability.

vendor/github.com/pebbe/zmq4/ctxoptions_windows.go

@@ -0,0 +1,44 @@
+// +build windows
+
+package zmq4
+
+/*
+Sets the scheduling policy for internal context’s thread pool.
+
+This option requires ZeroMQ version 4.1, and is not available on Windows.
+
+Supported values for this option can be found in sched.h file, or at
+http://man7.org/linux/man-pages/man2/sched_setscheduler.2.html
+
+This option only applies before creating any sockets on the context.
+
+Default value: -1
+
+Returns ErrorNotImplemented41 with ZeroMQ version < 4.1
+
+Returns ErrorNotImplementedWindows on Windows
+*/
+func (ctx *Context) SetThreadSchedPolicy(n int) error {
+	return ErrorNotImplementedWindows
+}
+
+/*
+Sets scheduling priority for internal context’s thread pool.
+
+This option requires ZeroMQ version 4.1, and is not available on Windows.
+
+Supported values for this option depend on chosen scheduling policy.
+Details can be found in sched.h file, or at
+http://man7.org/linux/man-pages/man2/sched_setscheduler.2.html
+
+This option only applies before creating any sockets on the context.
+
+Default value: -1
+
+Returns ErrorNotImplemented41 with ZeroMQ version < 4.1
+
+Returns ErrorNotImplementedWindows on Windows
+*/
+func (ctx *Context) SetThreadPriority(n int) error {
+	return ErrorNotImplementedWindows
+}