use with-temp-buffer instead of find-file. This makes sure C-x b works
as expected.
fix regexp
allow org-pdf-directory without trailing slash
case-insensitive field names
my headline style
un-interactivise
Revert "allow org-pdf-directory without trailing slash"
this does not seem like a good fix.

a proper fix to this would be something like python's os.path.join, or
code that made sure the org-ref-pdf-directory is a directory.
This reverts commit 7d499aabb8641fc297c0dd0f5fc88c88fd5cf93c.
Revert "my headline style"
this was an unintentional part of the pull request.

I could consider a customizable variable for this.
This reverts commit d400dcfa351f763b1691d390454276998266b42e.
Merge branch 'master' into pull-17
removed interactive from a place that did not need it. removed progn from citation functions. it should not be needed there.
fixed a spelling error
removed another apparently unnecessary progn