Update to latest esp8266-driver

sarahmarshy · Bartek Szatkowski · commit b45500c0a08c · 2017-07-14T11:40:16.000+01:00
diff --git a/esp8266-driver.lib b/esp8266-driver.lib
@@ -1 +1 @@
-https://github.com/armmbed/esp8266-driver/#dc37b65ca877d969aa492f348626df6e1b0b1df0
+https://github.com/armmbed/esp8266-driver/#cac4d0d8f97745fe9a613b705b406646aeacc3e2

Original file line number	Diff line number	Diff line change
`@@ -1 +1 @@`
`1`		`-https://github.com/armmbed/esp8266-driver/#dc37b65ca877d969aa492f348626df6e1b0b1df0`
	`1`	`+https://github.com/armmbed/esp8266-driver/#cac4d0d8f97745fe9a613b705b406646aeacc3e2`