Win wsa select event (#342)

* Fix #323: Missing SelectInterrupt implementation for Windows

Using WSAEventSelect, WSAWaitForMultipleEvents and WSAEnumNetworkEvents to emulate poll() with an interrupt-event.

* Cleanup

* Fixed incomplete comment.

* Switched ifdefs to support other Unixes with pipe file descriptors

* Fixed: SelectInterrupt fallback code for getFd()==-1 && getEvent()==nullptr converted a PollResultType::Timeout into a ReadyForRead causing the HttpClient to fail because it uses a hard-coded "SelectInterrupt" instance that doesn't implement getFd() and getEvent().

* Fixed gcc compile errors

* - HttpClient now uses the SelectInterruptFactory
- Fixed wrong ix::poll result when using Windows WSA functions

* We must deselect the networkevents from the socket event. Otherwise the socket will report states that aren't there.

ixwebsocket/IXSelectInterruptEvent.h

@@ -0,0 +1,39 @@
+/*
+ *  IXSelectInterruptEvent.h
+ */
+
+#pragma once
+
+#include "IXSelectInterrupt.h"
+#include <mutex>
+#include <stdint.h>
+#include <string>
+#include <deque>
+#ifdef _WIN32
+#include <windows.h>
+#endif
+
+namespace ix
+{
+    class SelectInterruptEvent final : public SelectInterrupt
+    {
+    public:
+        SelectInterruptEvent();
+        virtual ~SelectInterruptEvent();
+
+        bool init(std::string& /*errorMsg*/) final;
+
+        bool notify(uint64_t value) final;
+        bool clear() final;
+        uint64_t read() final;
+        void* getEvent() const final;
+    private:
+        // contains every value only once, new values are inserted at the begin, nu
+        std::deque<uint64_t> _values;
+        std::mutex _valuesMutex;
+#ifdef _WIN32
+        // Windows Event to wake up the socket poll
+        HANDLE _event;
+#endif
+    };
+} // namespace ix