Add BBB Ubuntu to platform detection.

Author: tdicola

Adafruit_GPIO/Platform.py

@@ -47,6 +47,11 @@ def platform_detect():
 	# Linux-3.8.13-bone47-armv7l-with-debian-7.4
 	elif plat.lower().find('armv7l-with-debian') > -1:
 		return BEAGLEBONE_BLACK
+	# Handle Beaglebone Black
+	# Platform output on Ubuntu ~July 2014:
+	# Linux-3.8.13-bone56-armv7l-with-Ubuntu-14.04-trusty
+	elif plat.lower().find('armv7l-with-ubuntu') > -1:
+		return BEAGLEBONE_BLACK	
 	else:
 		return UNKNOWN