Write notebook server info file in security directory
Test for writing and removing server info files
Fix writing server info files on Python 2
Command line entry point to list running notebook servers
Make names in JSON more consistent as per @ellisonbg's suggestion.
be conservative about kernel_info implementation

in case kernels don't comply with the message spec by leaving out the language key.
Merge pull request #4797 from minrk/safer-guiref

be conservative about kernel_info implementation
Merge pull request #4772 from takluyver/nbserver-files

Notebook server info files
Merge pull request #4788 from minrk/warn-pylab-notebook

warn when notebook is started in pylab mode
prefer marked to pandoc for markdown2html

better consistency with live notebook
don't require mathjax on the page in mathjax utils

required for reusing mathjaxutils in node
allow utils.js to be loaded in node

where navigator is undefined
add marked.js entry point for md2html in nbconvert

now uses the exact same code as the live notebook