* doc/xscanimage.man src/xscanimage.c src/xscanimage-gimp-1_0-compat.h:
Implemented (again) support for SANE_DEFAULT_DEVICE. If set, the
suitable backend is preselected in the device dialog. Use new Gimp
API, added compatibility file for old Gimp API (from xsane).
* TODO: Removed entry about SANE_DEFAULT_DEVICE and new Gimp API.
* TODO: Entries about SANE_DEFAULT_DEVICE and DBG output.
* src/xscanimage.c: Added suport for DBG messages. Added only a
few messages including a more verbose output when xscanimage
can't find any devices. Added support for SANE_DEFAULT_DEVICE.
* doc/xscanimage.man: Documented support for SANE_DEFAULT_DEVICE and
SANE_DEBUG_XSCANIMAGE.