Fixed typos, added pinmap example to dump map

lib/GpioMapper/WiringPiMapper.php

@@ -20,6 +20,7 @@
 namespace NoccyLabs\Gpio\GpioMapper;
 
 use NoccyLabs\Gpio\GpioMapperInterface;
+use NoccyLabs\Gpio\Exception\GpioException;
 
 class WiringPiMapper implements GpioMapperInterface
 {
@@ -107,7 +108,7 @@ class WiringPiMapper implements GpioMapperInterface
             case 19:    return 30;
             case 20:    return 31;
         }
-        throw new GpioException("Unable to map logicak {$logical} to GPIO pin");
+        throw new GpioException("Unable to map logical pin {$logical} to GPIO pin");
     }
 
 }