Blinking LED example

Revision:
0:7631f52d72e1
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-os.lib	Tue May 01 17:13:32 2018 +0000
@@ -0,0 +1,1 @@
+https://github.com/ARMmbed/mbed-os/#c05d72c3c005fbb7e92c3994c32bda45218ae7fe