Move activeBufferChanged listener to WeechatCtrl

I don't believe that the inputBar directive should know about the
mobile cutoff we have set for GB. We should aim to make it as
reusable as possible

js/glowingbear.js

@@ -497,6 +497,13 @@ weechat.controller('WeechatCtrl', ['$rootScope', '$scope', '$store', '$timeout',
 
     $scope.mobile_cutoff = 968;
 
+    // Focuses itself when active buffer is changed
+    $rootScope.$on('activeBufferChanged', function() {
+        if (document.body.clientWidth >= $scope.mobile_cutoff) {
+            $('#sendMessage').focus();
+        }
+    });
+
     $rootScope.countWatchers = function () {
         var root = $(document.getElementsByTagName('body'));
         var watchers = [];
@@ -1007,23 +1014,17 @@ weechat.directive('inputBar', function() {
     return {
 
         templateUrl: 'directives/input.html',
+        
         scope: {
             inputId: '@inputId',
         },
+
         controller: function($rootScope,
                              $scope,
                              $element,
                              connection,
                              models) {
 
-            // Focuses itself when active buffer is changed
-            $rootScope.$on('activeBufferChanged', function() {
-                if (document.body.clientWidth >= $scope.mobile_cutoff) {
-                    angular.element('#sendMessage').focus();
-                }
-            });
-
-
             /*
              * Returns the input element
              */