bumped version in README

Credits: https://github.com/LarsWH
Excerpt from PR:
```
Hi,

I added support for 'RC5 extended' in order to make this project:
https://www.instructables.com/id/Remote-Control-for-Lava-mMotion-Swing-Mounting-Bra/

The modification is working nicely in this single application. It has
not been tested elsewhere.

(I am new to Git and this is my first pull request ever. So please
excuse me if I have messed something up)

Kind regards,
Lars
```

Merged #522

IRremote.h

@@ -270,6 +270,7 @@ class IRsend
 		//......................................................................
 #		if SEND_RC5
 			void  sendRC5        (unsigned long data,  int nbits) ;
+			void  sendRC5ext     (unsigned long addr, unsigned long cmd, boolean toggle);
 #		endif
 #		if SEND_RC6
 			void  sendRC6        (unsigned long data,  int nbits) ;

README.md

@@ -8,7 +8,7 @@ This library enables you to send and receive using infra-red signals on an Ardui
 
 Tutorials and more information will be made available on [the official homepage](http://z3t0.github.io/Arduino-IRremote/).
 
-## Version - 2.2.3
+## Version - 2.4.3
 
 ## Installation
 1. Navigate to the [Releases](https://github.com/z3t0/Arduino-IRremote/releases) page.

changelog.md

@@ -1,8 +1,5 @@
-## 3.0.0 - 2017/09/14
-- Changed default send pin on ATmega32u4 from 13 to 9.
-	Note: this is a non-backwards compatible change as the behaviour of existing programs using this board for receiving WILL be affected. If you would like to use pin 13 as before then please search src/boarddefs.h for "32u4" and comment the line for pin 9 while uncommenting the line for pin 13
-
-
+## 2.4.3
+- Added Philips Extended RC-5 protocol support [PR #522] (https://github.com/z3t0/Arduino-IRremote/pull/522)
 
 ## 2.3.3 - 2017/03/31
 - Added ESP32 IR receive support [PR #427](https://github.com/z3t0/Arduino-IRremote/pull/425)

ir_RC5_RC6.cpp

@@ -78,6 +78,73 @@ void  IRsend::sendRC5 (unsigned long data,  int nbits)
 
 	space(0);  // Always end with the LED off
 }
+
+void  IRsend::sendRC5ext (unsigned long addr, unsigned long cmd, boolean toggle)
+{
+	// Set IR carrier frequency
+	enableIROut(36);
+	
+	unsigned long addressBits = 5;
+	unsigned long commandBits = 7;
+	unsigned long nbits = addressBits + commandBits;
+	
+	// Start
+	mark(RC5_T1);
+	
+	// Bit #6 of the command part, but inverted!
+	unsigned long cmdBit6 = (1UL << (commandBits-1)) & cmd;
+	if (cmdBit6) {
+		// Inverted (1 -> 0 = mark-to-space)
+		mark(RC5_T1);
+		space(RC5_T1);
+	} else {
+		space(RC5_T1);
+		mark(RC5_T1);
+	}
+	commandBits--;
+
+	// Toggle bit
+	static int toggleBit = 1;
+	if (toggle) {
+		if (toggleBit == 0) {
+			toggleBit = 1;
+		} else {
+			toggleBit = 0;
+		}
+	}
+	if (toggleBit) {
+		space(RC5_T1);
+		mark(RC5_T1);
+	} else {
+		mark(RC5_T1);
+		space(RC5_T1);
+	}
+
+	// Address
+	for (unsigned long  mask = 1UL << (addressBits - 1);  mask;  mask >>= 1) {
+		if (addr & mask) {
+			space(RC5_T1); // 1 is space, then mark
+			mark(RC5_T1);
+		} else {
+			mark(RC5_T1);
+			space(RC5_T1);
+		}
+	}
+	
+	// Command
+	for (unsigned long  mask = 1UL << (commandBits - 1);  mask;  mask >>= 1) {
+		if (cmd & mask) {
+			space(RC5_T1); // 1 is space, then mark
+			mark(RC5_T1);
+		} else {
+			mark(RC5_T1);
+			space(RC5_T1);
+		}
+	}
+
+	space(0);  // Always end with the LED off
+}
+
 #endif
 
 //+=============================================================================