Remove .gitattributes to eliminate "text=auto".

"text=auto" causes git to want to change the line endings on plf_colony.h
from CRLF to LF on every checkout, leaving changes in your working directory.
Then if you `git commit -a`, those changed line endings get committed!
https://stackoverflow.com/questions/5834014/lf-will-be-replaced-by-crlf-in-git-what-is-that-and-is-it-important

Removing "text=auto" solves this problem.

The only other stuff in this file was related to file types that
don't appear in SG14's repo.