SDFileSystem test for mbed OS 5

Dependencies:   SDFileSystem

Revision:
0:648259a2341c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-os.lib	Tue Aug 16 22:03:01 2016 +0000
@@ -0,0 +1,1 @@
+https://github.com/ARMmbed/mbed-os/#0993ae540c5c4b5ce3004bead1aefc0c6d1b3ea0