Added preliminary support for a panning canvas command.

Found that the iOS/Android export tool do not support at least one command from history file which was my main source to decode the history format. That command is likely to be linked with panning the canvas.

sample_tools/ptcr2gif.py

@@ -97,6 +97,7 @@ class CommandHandler:
             b'\xF5': self.replace_color,
             b'\xF6': self.erase_pixel,
             b'\xF7': self.clear_canvas,
+            b'\xF8': self.pan_canvas,
             #
             b'\xFA': self.set_color,
             b'\xFB': self.set_canvas_resolution,
@@ -221,6 +222,17 @@ class CommandHandler:
         # Always read 3 bytes (2 for stroke, 1 for ?)
         return 3
 
+    def pan_canvas(self):
+        self._was_a_stroke = True
+        self._get_stroke_number()
+
+        # This may be panning, not sure.
+
+        data = self._file.read(3)
+        data = struct.unpack("BBB", data)
+
+        return 5
+
     def set_color(self):
         self._was_a_stroke = False
         data = self._file.read(2)