Adding different dewarping algorithm as external option

[maximka1812]

I experimented with different dewarping algorithms and how they work if you want mostly automatic high quality result

This one turned out the best for now:

• Description - https://mzucker.github.io/2016/08/15/page-dewarping.html
• Code (with actual python support) - https://github.com/tachylatus/page_dewarp

Note that this code work with native resolution during transformation and also makes binarization always. Instead I use 2x bicubic upsampling for input and output grayscale version.

Idea can be to allow ST to be able to call external software (may be Windows only) for processing page (as external file) on early stage right before making page angle adjustments.

Note that referenced dewarping also usually correctly turns the page.