Added the resetIRQ method which resets the IR pin on the PCF

src/libs/PCF8574/PCF8574.cpp

@@ -104,3 +104,10 @@ void PCF8574::getPinModeAll(boolean array[8])
 	array[6] = (_pddr & P6) == 0 ? INPUT : OUTPUT;
 	array[7] = (_pddr & P7) == 0 ? INPUT : OUTPUT;
 }
+
+void PCF8574::resetIRQ()
+{
+	//We request 1 byte in order to reset the IRQ
+	_twc.requestFrom((uint8_t)_address,(uint8_t)1,(uint8_t)true);
+	 while(_twc.available())_twc.read();
+}

src/libs/PCF8574/PCF8574.h

@@ -23,6 +23,8 @@ class PCF8574
 	boolean getPinMode(Pin pin);
 	void getPinModeAll(boolean array[8]);
 	void togglePin(Pin pin);
+	//Reset the IRQ by doing a dummy read
+	void resetIRQ();
   private:
     TwoWire &_twc;
     uint8_t _address;

src/libs/PCF8574/keywords.txt

@@ -16,6 +16,7 @@ digitalReadAll	KEYWORD2
 getPinMode	KEYWORD2
 getPinModeAll	KEYWORD2
 togglePin	KEYWORD2
+resetIRQ	KEYWORD2
 
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 # Constants (LITERAL1)