Changes

Summary

1. fix GIFReadWriter>>readExtensionBlock:withFrame:  to support Comment (details)

Commit 8af6d2bbcf01ad3bf3b3d5edb56ec542886ce7d5 by eiichiro.ito fix GIFReadWriter>>readExtensionBlock:withFrame:  to support Comment Extension.
	src/Graphics-Files/GIFReadWriter.class.st (diff)