Some changes made

- Bugfix in display.brightness
- Created brightness-exampe.py

Author: gheinzer

examples/brightness/brightness-example.py

@@ -0,0 +1,15 @@
+from nextion import nextion
+import time
+
+display = nextion(12, 13, 9600)
+display.brightness(50)
+time.sleep_ms(500)
+display.brightness(60)
+time.sleep_ms(500)
+display.brightness(70)
+time.sleep_ms(500)
+display.brightness(80)
+time.sleep_ms(500)
+display.brightness(90)
+time.sleep_ms(500)
+display.brightness(100)

nextion.py

@@ -21,5 +21,5 @@ def page(self, page):
     def reset(self):
         self.cmd("rest")
     def brightness(self, brightness):
-        self.cmd("dim=" + brightness)
+        self.cmd("dim=" + str(brightness))