This adheres more closely to the specs, especially Atom, where the
'description' arg becomes <summary>.
Note that this means full article content will no longer appear in RSS
feeds.
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.
