Treat .wdp files as JXR images.
Treat .wdp files as JXR images.

This file extension seems to be from before JXR was formally
standardized and was still just a MS project, but might as well support
it here since there are still tools that use this by default.

Closes #142.

weilitao/flambe,weilitao/flambe,playedonline/flambe,Disar/flambe,mikedotalmond/flambe,mikedotalmond/flambe,markknol/flambe,markknol/flambe,weilitao/flambe,aduros/flambe,Disar/flambe,playedonline/flambe,mikedotalmond/flambe,Disar/flambe,aduros/flambe,Disar/flambe,mikedotalmond/flambe,aduros/flambe,playedonline/flambe,weilitao/flambe,playedonline/flambe,aduros/flambe,markknol/flambe