Fixed disqus_helper in mako templates

Page title is escaped safely with json.dumps(..) to support titles
containing quotes
Update nikola/plugins/command_init.py

Now, tuple!
Fixed disqus_helper in Jinja templates

To make it work, a new {{ ..|tojson }} filter is registered.
Merge pull request #234 from imankulov/disqus_fix

Fixed disqus_helper in mako templates
[FIX] don't copy .html sources (it it does, error of two target for diferent tasks raised)
updated changelog
updated to current css from docutils
updated jquery-mustache location
make rst title detection less greedy
txt2tags markup support
bbcode support
unbreak travis
more travis unbreaking
Using the filename as slug if no slug is found in the metadata.
Gist support
oops
Added Catalá translation
make bbcode more optional
hide metadata
Make it possible to extract metadata from a file by using regexp.