This replaces all `http://` and `//:` links with `https:`. The protocol-
relative URL scheme is now deemed to be an anti-pattern. There are
security advantages to using HTTPS, and there are no significant
performance concerns.
In short, if the asset we need is available via HTTPS, then that asset
should always be loaded via HTTPS.
Fixes#1736
reverts getpelican/pelican@ddcccfeaa9
If one used a locale that made use of unicode characters (like fr_FR.UTF-8)
the files on disk would be in correct locale while links would be to C.
Uses a SafeDatetime class that works with unicode format strigns
by using custom strftime to prevent ascii decoding errors with Python2.
Also added unicode decoding for the calendar module to fix period
archives.
