Style resend button as an inline link

For messages that failed to send due to network errors, this change
allows retrying them directly from the main conversation view rather
than only from the message detail view.

// FREEBIE

js/models/messages.js

@@ -211,6 +211,14 @@
             this.set({errors: errors});
         },
 
+        hasNetworkError: function(number) {
+            var error = _.find(this.get('errors'), function(e) {
+                return (e.name === 'MessageError' ||
+                        e.name === 'OutgoingMessageError' ||
+                        e.name === 'SendMessageNetworkError');
+            });
+            return !!error;
+        },
         removeOutgoingErrors: function(number) {
             var errors = _.partition(this.get('errors'), function(e) {
                 return e.number === number &&