fix: Report fatal errors as indeed "fatal" (#425)

Author: dustinblackman

lib/client.js

@@ -161,7 +161,7 @@ extend(Raven.prototype, {
         // also we want to make sure we don't go recursion crazy if more errors happen after this one
         firstError = err;
         caughtFirstError = true;
-        self.captureException(err, function(sendErr, eventId) {
+        self.captureException(err, {level: 'fatal'}, function(sendErr, eventId) {
           if (!calledFatalError) {
             calledFatalError = true;
             self.onFatalError(err, sendErr, eventId);