Merge branch 'Rotule666-digital-output-pin-initialization'

Thanks @Rotule666 for spotting this quite lax coding there.
I've further improved it by adding a proper default behaviour
in case the function letter is unknown or misspelt.

pyfirmata2/pyfirmata2.py

@@ -285,7 +285,11 @@ def get_pin(self, pin_def):
                 pin.mode = SERVO
             elif bits[2] == 'u':
                 pin.mode = INPUT_PULLUP
-            elif bits[2] != 'o':
+            elif bits[2] == 'i':
+                pin.mode = INPUT
+            elif bits[2] == 'o':
+                pin.mode = OUTPUT
+            else:
                 pin.mode = INPUT
         else:
             pin.enable_reporting()