fixed get_brightness for multiple displays

issue #14 
resolved : TypeError: unsupported operand type(s) for /: 'float' and 'list'

get_brightness() returns a list if multiple displays are detected,
To fix this pass display=0 to get_brightness().
i.e. : sbcontrol.get_brightness(display=0)

src/Gesture_Controller.py

@@ -289,13 +289,13 @@ def getpinchxlv(hand_result):
 
     def changesystembrightness():
         """sets system brightness based on 'Controller.pinchlv'."""
-        currentBrightnessLv = sbcontrol.get_brightness()/100.0
+        currentBrightnessLv = sbcontrol.get_brightness(display=0)/100.0
         currentBrightnessLv += Controller.pinchlv/50.0
         if currentBrightnessLv > 1.0:
             currentBrightnessLv = 1.0
         elif currentBrightnessLv < 0.0:
             currentBrightnessLv = 0.0       
-        sbcontrol.fade_brightness(int(100*currentBrightnessLv) , start = sbcontrol.get_brightness())
+        sbcontrol.fade_brightness(int(100*currentBrightnessLv) , start = sbcontrol.get_brightness(display=0))
 
     def changesystemvolume():
         """sets system volume based on 'Controller.pinchlv'."""
@@ -597,4 +597,4 @@ def start(self):
 
 # uncomment to run directly
 # gc1 = GestureController()
-# gc1.start()
+# gc1.start()