Support for pdf-tools

[McSinyx]

Since doc-view's display quality is terrible, I think I'm not the only one who uses pdf-tools instead for PDF. However, I cannot see if there's a way to manually revert pdf-tools buffer to replace the function doc-view-revert-buffer. auto-revert-mode doesn't help though.

[jsinglet]

Thanks for the details; if there is more demand for this I'll try to add it in a future release. PRs are also welcome :)

[thinkoid]

FWIW, I took a look at the code and it seems to me that the enhancement only asks for differentiating between major modes. I cobbled something together here but my LISP-ing is very rudimentary. HTH