HTML page <title> to lowercase
Fixing: foo.md leads now to foo/index.html

Seems to be a Jekyll problem (bug, maybe): when using permalinks !=
pretty:

  foo.md -> foo.html
  --> http://host/foo.html

while I want:

  foo.md -> foo/index.html
  --> http://host/foo/

Note: this problem did not show up on GitHub Pages, only locally!