* 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.