Feature/connection state (#25)

* (cmake) add a warning about 32/64 conversion problems.

* fix typo

* New connection state for server code + fix OpenSSL double init bug

* update README

ixwebsocket/IXConnectionState.cpp

@@ -0,0 +1,37 @@
+/*
+ *  IXConnectionState.cpp
+ *  Author: Benjamin Sergeant
+ *  Copyright (c) 2019 Machine Zone, Inc. All rights reserved.
+ */
+
+#include "IXConnectionState.h"
+
+#include <sstream>
+
+namespace ix
+{
+    std::atomic<uint64_t> ConnectionState::_globalId(0);
+
+    ConnectionState::ConnectionState()
+    {
+        computeId();
+    }
+
+    void ConnectionState::computeId()
+    {
+        std::stringstream ss;
+        ss << _globalId++;
+        _id = ss.str();
+    }
+
+    const std::string& ConnectionState::getId() const
+    {
+        return _id;
+    }
+
+    std::shared_ptr<ConnectionState> ConnectionState::createConnectionState()
+    {
+        return std::make_shared<ConnectionState>();
+    }
+}
+