Update Dates for IPython 4.0 EOL and 5.0-release.

Author: Carreau

site.js

@@ -113,8 +113,8 @@ $(document).ready(function (){
       {content: '1.x', start: '2013-08-08', end:'2014-03-31', py2:true},
       {content: '2.x', start: '2014-04-01', end:'2015-02-26', py2:true},
       {content: '3.x', start: '2015-02-27', end:'2015-08-10', py2:true},
-      {content: '4.x', start: '2015-08-11', end:'2016-05-31', py2:true},
-      {content: 'IPython 5.x LTS', start: '2016-06-01', end:'2019-06-01', py2:true},
+      {content: '4.x', start: '2015-08-11', end:'2016-07-07', py2:true},
+      {content: 'IPython 5.x LTS', start: '2016-07-08', end:'2019-06-01', py2:true},
       {content: '6.x', start: '2017-01-01', end:'2018-01-01'},
       {content: '7.x', start: '2018-01-01', end:'2019-06-12'},
       {content: '8.x', start: '2019-06-12', end:'2020-06-01'},