add support for Bitsy 7.10; turn dithering off by default; more help text

src/lib.rs

@@ -41,7 +41,7 @@ lazy_static! {
             image:      None,
             room_name:  None,
             palette:    SelectedPalette::None,
-            dither:     true,
+            dither:     false,
             brightness: 0,
         }
     );