Log Message:
Update to 3.20161219. From the changelog:

[ Joey Hess ]
* inline: Prevent creating a file named ".mdwn" when the
  postform is submitted with an empty title.

[ Simon McVittie ]
* Security: tell `git revert` not to follow renames. If it does, then
  renaming a file can result in a revert writing outside the wiki srcdir
  or altering a file that the reverting user should not be able to alter,
  an authorization bypass. Thanks, intrigeri
* cgitemplate: remove some dead code. Thanks, blipvert
* Restrict CSS matches against header class to not break
  Pandoc tables with header rows. Thanks, karsk
* Make pagestats output more deterministic. Thanks, intrigeri