added bitmappedgpio class to map several gpio in one byte

examples/bitmap.php

@@ -0,0 +1,24 @@
+<?php
+
+require_once __DIR__."/../vendor/autoload.php";
+
+/*
+ * This example demonstrates mapping GpioPins to bit values and writing bits
+ * in parallel.
+ *
+ */
+
+use NoccyLabs\Gpio\Gpio;
+use NoccyLabs\Gpio\Util\BitmappedGpio;
+use NoccyLabs\Gpio\GpioMapper\WiringPiMapper;
+
+$gpio = new Gpio();
+$gpio->setMapper( new WiringPiMapper(2) );
+
+$par = new BitmappedGpio();
+for($n = 0; $n < 7; $n++) {
+    $par->setGpioPin($n,$gpio[$n]);
+}
+
+$par->write(0xFF);
+$par->write(0x00);