Fixed Marquee bug with periods

Author: Melissa LeBlanc-Williams

adafruit_featherwing/alphanum_featherwing.py

@@ -56,7 +56,7 @@ def print(self, value):
             from adafruit_featherwing import alphanum_featherwing
 
             display = alphanum_featherwing.AlphaNumFeatherWing()
-            display.print(1234)
+            display.print(123)
 
         """
         self._seg14x4.print(value)
@@ -90,6 +90,8 @@ def marquee(self, text, delay=0.25, loop=True):
     def _scroll_marquee(self, text, delay):
         for character in text:
             self._seg14x4.scroll()
+            if character == '.':
+                self._seg14x4[3] = ' ';
             self._seg14x4[3] = character
             sleep(delay)
             self._seg14x4.show()