Correct URLs that have crept into the notmuch codebase with http://
when https:// is possible.
As part of this conversion, this changeset also indicates the current
preferred upstream URLs for both gmime and sup. the new URLs are
https-enabled, the old ones are not.
This also fixes T310-emacs.sh, thanks to Bremner for catching it.
html_static_path is a kind of source directory and it was set to
destination directory (../html) which caused infinite recursion with
Sphinx 1.2 and above.
