migrate to async IO model

new PIIODevice::interrupt() virtual method
new PIWaitEvent private class
PIEthernet and PISerial basically tested on Windows and Linux

libs/main/cloud/picloudserver.h

@@ -51,6 +51,7 @@ public:
 		ssize_t writeDevice(const void * data, ssize_t size) override;
 		DeviceInfoFlags deviceInfoFlags() const override {return PIIODevice::Reliable;}
 		ssize_t bytesAvailable() const override {return buff.size();}
+		void interrupt() override;
 
 	private:
 		void pushBuffer(const PIByteArray & ba);
@@ -74,6 +75,7 @@ protected:
 	ssize_t readDevice(void * read_to, ssize_t max_size) override;
 	ssize_t writeDevice(const void * data, ssize_t max_size) override;
 	void stopThreadedReadDevice() override;
+	void interrupt() override;
 
 private:
 	EVENT_HANDLER1(void, _readed, PIByteArray &, ba);