[CI] use sphinx < 1.6 for some reason, the readthedocs sphinx ext doesn't seem to register correctly on sphinx >=1.6, presumably related to the transition to using entry points. For now, just use <1.6
[CI] use sphinx < 1.6
for some reason, the readthedocs sphinx ext doesn't seem to
register correctly on sphinx >=1.6, presumably related to the
transition to using entry points. For now, just use <1.6

juhasch/IPython-notebook-extensions,ipython-contrib/IPython-notebook-extensions,jcb91/IPython-notebook-extensions,jcb91/IPython-notebook-extensions,ipython-contrib/IPython-notebook-extensions,ipython-contrib/IPython-notebook-extensions,juhasch/IPython-notebook-extensions,ipython-contrib/IPython-notebook-extensions,juhasch/IPython-notebook-extensions,jcb91/IPython-notebook-extensions