Fix two gfx_RLETSprite bugs

These bugs occured when:
1. width != height
2. Clipping on right and an opaque run starts at exactly xmax

The example is improved/updated to cover these cases.

Author: runer112

examples/gfx_rletsprite/autotester.json

@@ -18,7 +18,7 @@
       "description": "Make sure the sprites are displayed properly",
       "start": "vram_start",
       "size": "vram_8_size",
-      "expected_CRCs": [ "7C9ADADE" ]
+      "expected_CRCs": [ "28404387" ]
     },
     "2": {
       "description": "Back to the home screen (exit check)",