Add _layouts

commit="21b409c"
date="Sun May 18 10:51 2014 +0100"
git filter-branch --env-filter \
    "if test \$GIT_COMMIT = '$commit'
     then
         export GIT_AUTHOR_DATE
         export GIT_COMMITTER_DATE
         GIT_AUTHOR_DATE='$date'
         GIT_COMMITTER_DATE='$date'
     fi" &&
rm -fr "$(git rev-parse --git-dir)/refs/original/"