[ci] require trusty dist on travis to avoid complaints about the old 1.9.1 pandoc version provided on precise otherwise
[ci] require trusty dist on travis
to avoid complaints about the old 1.9.1 pandoc version provided on precise otherwise

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