pyocr: 0.4.4 -> 0.4.6

Upstream changes for version 0.4.5:

 * Clean up exceptions raised when OCR fails:
 * Now, all tools raise only exceptions inheriting from
   pyocr.PyocrException
 * There is now one and only one TesseractError (shared between
   pyocr.libtesseract and pyocr.tesseract)

Upstream changes for version 0.4.6:

 * hOCR outputs: Generate valid XHTML files

The full upstream changelog can be found at:

https://github.com/jflesch/pyocr/blob/master/ChangeLog



Note that because of the version bump of Tesseract neither version 0.4.4
nor version 0.4.6 succeed to build, so we need to fix this up soon.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>