Broken links in README

[Gabor Szarnyas]

Hi,

I just stumbled upon this paper - great work. One thing I noticed is that a couple of links in the README are broken:

• pushpull-icpp18-final.pdf
• LICENSE.md
• Scott Beamer's Direction-optimization paper

Best,
Gabor

[Carl Yang]

Hi Gabor,
Thank you for your kind words! I've fixed the links in the README.

Regards,
Carl