* convert/from_qimage.hh: New. convert an image2d to a QImage.

	* core/line_info.hh: Add a new member has_text.

	* text/recognition.hh: Remove an invalid precondition.

	* toolchain/nepomuk/text_extraction.hh: New. Specific toolchain
	for Nepomuk.

	* tests/Makefile.am: Add toolchain/* subdirs.

	* tests/toolchain/Makefile.am,
	* tests/toolchain/nepomuk/Makefile.am: New.

	* tests/img/wildly.pbm: New. New test image.

	* tests/toolchain/nepomuk/text_extraction.cc: New. New test.