Additional DigitalIn example

Revision:
0:10c4d3aa026e
Child:
1:ad8683db322a
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-os.lib	Thu Jan 19 14:21:24 2017 -0600
@@ -0,0 +1,1 @@
+https://github.com/ARMmbed/mbed-os/#34c1facf42a174f47fdf9002cd8c6bf10ac41744