Added buttons() method -- polls all buttons, returns bitmask

Author: PaintYourDragon

Adafruit_CharLCDPlate/Adafruit_CharLCDPlate.py

@@ -424,10 +424,16 @@ def backlight(self, color):
           self.i2c.address, self.MCP23017_GPIOB, self.portb)
 
 
+    # Read state of single button
     def buttonPressed(self, b):
         return (self.i2c.readU8(self.MCP23017_GPIOA) >> b) & 1
 
 
+    # Read and return bitmask of combined button state
+    def buttons(self):
+        return self.i2c.readU8(self.MCP23017_GPIOA) & 0b11111
+
+
     # ----------------------------------------------------------------------
     # Test code