js: drop excanvas used for IE 8 support

docs/contributing.rst

@@ -85,8 +85,8 b' whitespace noise in your patches.'
 We support both Python 2.6.x and 2.7.x and nothing else. For now we don't care
 about Python 3 compatibility.
 
-We try to support the most common modern web browsers. IE8 is still supported
-to the extent it is feasible but we may stop supporting it very soon.
+We try to support the most common modern web browsers. IE9 is still supported
+to the extent it is feasible, IE8 is not.
 
 We primarily support Linux and OS X on the server side but Windows should also work.
 

kallithea/templates/base/root.html

@@ -63,9 +63,6 b''
         <script type="text/javascript" src="${h.url('/js/bootstrap.js', ver=c.kallithea_version)}"></script>
         <script type="text/javascript" src="${h.url('/js/select2/select2.js', ver=c.kallithea_version)}"></script>
         <script type="text/javascript" src="${h.url('/js/mousetrap.js', ver=c.kallithea_version)}"></script>
-        <!--[if lt IE 9]>
-           <script language="javascript" type="text/javascript" src="${h.url('/js/excanvas.min.js')}"></script>
-        <![endif]-->
         <script type="text/javascript" src="${h.url('/js/yui.flot.js', ver=c.kallithea_version)}"></script>
         <script type="text/javascript" src="${h.url('/js/native.history.js', ver=c.kallithea_version)}"></script>
         <script type="text/javascript" src="${h.url('/js/pyroutes_map.js', ver=c.kallithea_version)}"></script>