A digital input monitoring implementation with an interrupt.

Revision:
0:501aab314b48
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-os.lib	Mon Sep 26 16:26:06 2016 +0000
@@ -0,0 +1,1 @@
+https://github.com/ARMmbed/mbed-os/#21dd7008a1540c02150f1b87c12294301db979bb