check program for USB Serial

Dependencies:   USBDevice

Revision:
0:941291e23892
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Thu Aug 03 13:27:41 2017 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/mbed/builds/a97add6d7e64
\ No newline at end of file