Lab 2 answer to part 2

Fork of digitalInInterrupt_sample by William Marsh

Revision:
3:05b6a1431a6b
diff -r 071f22412cdc -r 05b6a1431a6b mbed-os.lib
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-os.lib	Tue Jan 16 18:14:21 2018 +0000
@@ -0,0 +1,1 @@
+https://github.com/ARMmbed/mbed-os/#96d9a00d0a1d25095b330095fa81c40f7741777c