Datatype for WebP images (Google's new image format).
See http://code.google.com/speed/webp for more details.

Big thankyou to Michael Trebilcock for his port of libvpx which
made this possible.

v1.6 (25/09/2012)
* Now supports alpha transparency (with webp.library v4)

v1.5 (29/07/2011)
* Now supports DTM_WRITE for writing WebP files.

v1.4 (21/03/2011)
* Remodelled to use webp.library
  -> For updates see http://www.unsatisfactorysoftware.co.uk/

v1.3 (03/10/2010)
* Updated to libvpx 0.9.2 - dynamically linked for future updates.

v1.2 (02/10/2010)
* Remove debug, squash memory leak

v1.1 (02/10/2010)
* First release