Refactored code and a lot of improvements in speed and file reading

[Huggyturd]

<<< I'am not a native in English >>> Hello! I discovered this project in my searches for machine generation of anki decks from books. I am a programmer with some experience and I make some improvements in the code and add new features. Now you be able to convert pdf, epub e web pages in a nice manner and a problem with gpu memory when using cuda it's resolved. I was able to convert a pdf file with 900 pages with a gtx 1050 ti in approximately 1.2 hour.

[thiswillbeyourgithub]

Hi and thanks a LOT for the interest in this project,

I was among the ones who tried to implement pdf and epub feature. I was very surprised at the lack of uniformity among those files, making it very tricky to always correclty parse text.

Are you confident that your solution works? Have you tested it on different files?