Read status of buttons on D5-D7 of PCF8574. Turn on corresponding led D0-D3.

Dependencies:   PCF8574 mbed

Revision:
0:c862449fe089
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/PCF8574.lib	Mon Apr 04 20:59:46 2016 +0000
@@ -0,0 +1,1 @@
+http://developer.mbed.org/users/simon/code/PCF8574/#ec8da0c59403