json test

Revision:
0:2ee762ea11b3
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-os.lib	Fri Jan 26 06:05:31 2018 +0000
@@ -0,0 +1,1 @@
+https://github.com/ARMmbed/mbed-os/#5f6572179d66ce4c09d6517b659ac51133cc980d