Add experimental rgb and rgba attributes to Console.

I want to test using these names for this attribute but don't want to
officially add another name for the same thing until I know these work
well in practice.

Author: HexDecimal

tcod/console.py

@@ -294,6 +294,16 @@ def tiles2(self) -> np.ndarray:
         """
         return self.tiles_rgb
 
+    @property
+    def rgba(self) -> np.ndarray:
+        # This attribute is provisional and may be changed at anytime.
+        return self.tiles
+
+    @property
+    def rgb(self) -> np.ndarray:
+        # This attribute is provisional and may be changed at anytime.
+        return self.tiles_rgb
+
     @property
     def default_bg(self) -> Tuple[int, int, int]:
         """Tuple[int, int, int]: The default background color."""