When a notebook is written to file, name the metadata name u''.
Use a CDN to get reveal.js library.
Make configurable the url where look for reveal.js library.
Fixing typo in reveal.tpl.
Added some changes covering Mathias's commentaries.
Added look for key 'reveal' to not overwrite it.
Nbconvert latex posix path fix
fix path prefix in nbconvert

there was a typo in a previous PR
set overflow-x: hidden on Firefox only

workaround crazy Firefox-only behavior when selecting newlines

closes #3549
Fixed posix path in sphinx transformer
Fix missing import os in latex exporter.
remove mention of nonexistent `_margv` in macro

closes #3476
Post review, some fixes made
convertoutputtransformer renamed to convertfiguretransformer
Shrunk logic, use merge built in to Config
renamed:    debugwriter.py -> debug.py
Yaml support