Fix issue loading as a JSM (fixes #28)

vendor/mozjexl.jsm

@@ -1,4 +1,4 @@
-/* eslint-disable */this["mozjexl.jsm"] =
+/* eslint-disable */this["mozjexl"] =
 /******/ (function(modules) { // webpackBootstrap
 /******/ 	// The module cache
 /******/ 	var installedModules = {};

webpack.config.js

@@ -12,7 +12,7 @@ module.exports = {
   output: {
     path: path.resolve(__dirname, "vendor/"),
     filename: "[name].jsm",
-    library: "[name].jsm",
+    library: "[name]",
     libraryTarget: "this"
   },
   plugins: [