tesseract-ocr jpeg support added

I just pushed some patches to the github host to add jpeg image support with libjpeg.

One drawback is that, because the image operation infrastructure in tesseract doesn’t allow passing libjpeg private structures between open and read operations, I have to open the file stream twice in opening and reading jpeg images.

To test the patch, pull from git://github.com/bergwolf/tesseract-ocr-copy.git and build tesseract-ocr. Then run some tests, this time against jpeg images :)