Log Message:
Changes 0.6.3:
* Fixed a use-after-free error in the GIF reader.
* Flushed the output log to display the current trial in real time.
* Fixed an error in reporting unrecognized file formats.
* Removed the requirement to "fix" TIFF files that contain unrecognized
  metadata.
* Simplified the option abbreviation rules. Option names can now be
  abbreviated to their shortest unique prefix, as in X11 applications.