Added an auto rename option and fixed the force option
Added an auto rename option and fixed the force option

I've noticed that if I am downloading two videos with same names from youtube (e.g. https://www.youtube.com/watch?v=606hmlA_nxw and https://www.youtube.com/watch?v=CLrXTnggUeY), only one of them will be saved (usually the bigger one according to the original script "os.path.getsize(output_filepath) >= total_size * 0.9"). However, I want them both while preserving their names from youtube. So I modified the source code. It looks like there are a lot of changes, but I just added an indent and everything changed.
Also, I've noticed that "force" is not working at all. I fixed that issue.
xyuanmu/you-get,xyuanmu/you-get