Update multiline plot for translation

[RekhaAngara]

#61

Adding a PR with the solution @veghp suggested

[veghp]

Thank you, yes this is the solution I had. There is one more thing to sort out before we merge: in some cases, a few letters are also translated on the line after the last line. See example:

test_translation.pdf

This is not related to the PDF conversion, or the crop method. I'll try and look into it, I think it will involve handling line_virtual_end properly.