Log Message:
Changes 6.8.9.0:
* Fixed bug with -strip failing to exclude PNG chunks
* Added new coder to take a screen shot of a monitor in Windows
* Don't transform sRGB compatible colorspaces to sRGB, doing so
  inadvertingly promotes colormapped images to DirectClass.
* Use temporary path rather then current working directory
* Support -canny edge detection option.
* Use MAGICKCORE_LIBOPENJP2_DELEGATE instead of MAGICKCORE_JP2_DELEGATE