Fix color swapping during shift()

This fixes the color swapping during shift() as noted in #102

adafruit_ht16k33/matrix.py

@@ -245,7 +245,7 @@ def pixel(self, x: int, y: int, color: Optional[int] = None) -> Optional[int]:
             super()._pixel(y, x, (color >> 1) & 0x01)
             super()._pixel(y + 8, x, (color & 0x01))
         else:
-            return super()._pixel(y, x) | super()._pixel(y + 8, x) << 1
+            return super()._pixel(y, x)  << 1 | super()._pixel(y + 8, x)
         return None
 
     def fill(self, color: int) -> None: