Add DISABLE_CLASS_COPY macro (and use it)

Use this macro to disallow copying of an object using the assignment
operator or copy constructor.  This catches otherwise silent-but-deadly
mistakes such as "ServerMap map = env->getMap();" at compile time.

If so desired, it is still possible to copy a class, but it now requires
an explicit call to memcpy or std::copy.

src/environment.h

@@ -137,6 +137,7 @@ protected:
 private:
 	Mutex m_time_lock;
 
+	DISABLE_CLASS_COPY(Environment);
 };
 
 /*