Abstract-PDF Switcher nga bits_and_scraps

When you visit an abstract or a pdf on one of the supported sites, an addressbar button will appear.
By clicking that button, you can switch from a pdf to an abstract and vice versa.
The following sites are currently supported:
  https://arxiv.org/
  https://export.arxiv.org/
  https://openreview.net/
  http://papers.nips.cc/
  http://papers.neurips.cc/
  http://proceedings.mlr.press/