Log Message:
Update libextractor to 0.4.2.

Fixes (second half of) Secunia SA: http://secunia.com/advisories/15651/
(first half was fixed in 0.3.11nb1)

ChangeLog excerpts:

Thu Feb 24 00:32:44 EST 2005
	Added extractor that extracts binary (!) thumbnails from
	images using ImageMagick.  Decoder function for the binary
	string is in the thumbnailextractor.c source.

Sun Feb 20 16:36:17 EST 2005
	Fixed similar problem in REAL extractor.  Added support
	for new Helix/Real format to REAL extractor.

Sun Feb 20 12:48:15 EST 2005
	Fixed (rare) integer overflow bug in PNG extractor.

Fri Jan 21 15:23:43 PST 2005
	Fixed security problem in PDF extractor.

Fri Dec 24 13:28:59 CET 2004
	Added support for Unicode to the pdf extractor.

Thu Dec 23 18:14:10 CET 2004
	Avoided exporting symbol OPEN (conflicts on OSX
	with same symbol from GNUnet).  Added conversion
	to utf8 to various plugqins (see todo) and
	added conversion from utf8 to current locale to
	print keywords.