add set/get variable methods in tesseract module

[chrox]

In this way we can generate hOCR file without recognition.

tesseract.tessedit_make_boxes_from_boxes = true;
tesseract.findText('hocr', 0);

[schulzch]

Nice work! I think this patch could be further improved by publishing Tesseract variables as JavaScript attributes (automatic type conversion, enumeration of all variables in Tesseract objects), like this:

tesseract.tessedit_make_boxes_from_boxes = 1;
// or using some magic:
tesseract.tesseditMakeBoxesFromBoxes = true;
tesseract.findText('hocr', 0);

Do you like this idea?

[chrox]

It will be really cool to enumerate Tesseract variables and convert them automatically to JavaScript attributes. The only way I can find to list available variables is calling Tesseract::PrintVariables API which requires a file stream(C FILE pointer) to receive variables dump. I'm wondering if it's OK to stream the dump to a tmp file and read back and parse the variables.

[schulzch]

Streaming and Parsing is way too complicated - GlobalParams() can be used for this ( see: baseapi.cpp:155 ).

[chrox]

Now all tesseract variables including global variables and member variables of Tesseract class are automatically converted to attributes in JavaScript object.

[schulzch]

Thanks a lot! I've applied it with some changes for MSVC.