Merge branch 'master' into dev_k20d5m_testing

Author: 0xc0170

README.md

@@ -1,5 +1,5 @@
-mbed SDK
-========
+mbed SDK 
+======== 
 
 [![Build Status](https://travis-ci.org/mbedmicro/mbed.png)](https://travis-ci.org/mbedmicro/mbed/builds)
 

libraries/mbed/api/InterruptIn.h

@@ -108,11 +108,13 @@ class InterruptIn {
      */
     void mode(PinMode pull);
 
-    /** Enable IRQ
+    /** Enable IRQ. This method depends on hw implementation, might enable one
+     *  port interrupts. For further information, check gpio_irq_enable().
      */
     void enable_irq();
 
-    /** Disable IRQ
+    /** Disable IRQ. This method depends on hw implementation, might disable one
+     *  port interrupts. For further information, check gpio_irq_disable().
      */
     void disable_irq();