* add youtube link for config readme * add youtube thumbnail for chrome clipboard
* add youtube link for config readme
* add youtube thumbnail for chrome clipboard

original-commit-id: 6fb5473c3465939b49826e6fb236fc339c5d3cd6
original-commit-url: https://github.com/ipython-contrib/IPython-notebook-extensions/commit/6fb5473c3465939b49826e6fb236fc339c5d3cd6

jcb91/jupyter_nbextensions_configurator,jcb91/jupyter_nbextensions_configurator,jcb91/jupyter_nbextensions_configurator,jcb91/jupyter_nbextensions_configurator