CCITTFaxDecoder: Support for pure one-dimensional encoding (Group 3, 1-D)

[cdecompilador]

link to sample pdf The pdf is just a random image scanned from my printer, it fails at filters/ccittfax.py:548

[maxpmaxp]

PDF specification supports 3 types of encoding depending on K value:

• K<0 - Pure 2-dimensional encoding (Group 4), which is suported by pdfreader
• K=0 - Pure one-dimensional encoding (Group 3, 1-D), - which is in use in this file and not supported at this point
• K>0 - Mixed one and two dimensional, not supported.

I treat as a feature request to start supporting pure one dimensional encodings.

See https://www.fileformat.info/mirror/egff/ch09_05.htm#CH09-DMYID.1.1

[maxpmaxp]

Attaching the sample file as the link in the first comment doesn't work. fax-G31D.pdf