store the custom HS/IS URL in local storage, add some review commentary

src/controllers/molecules/ServerConfig.js

@@ -48,6 +48,7 @@ module.exports = {
         });
     },
 
+    // XXX: horrible naming due to potential confusion between the word 'is' and the acronym 'IS'
     isChanged: function(ev) {
         this.setState({is_url: ev.target.value}, function() {
             this.props.onIsUrlChanged(this.state.is_url);

src/controllers/templates/Login.js

@@ -35,6 +35,7 @@ module.exports = {
 
     onHSChosen: function() {
         MatrixClientPeg.replaceUsingUrls(
+            // XXX: why is the controller invoking methods from the view? :( -matthew
             this.getHsUrl(),
             this.getIsUrl()
         );