Caterpillar now generates app.info.js, a metadata script. Resolves #12.

tests/js/polyfills/runtime.polyfill.test.js

Index: tests/js/polyfills/runtime.polyfill.test.js
diff --git a/tests/js/polyfills/runtime.polyfill.test.js b/tests/js/polyfills/runtime.polyfill.test.js
index caccaab0e40c9a0bf13e9c538680ac4e5326d3b1..9918e1b044ecd0d72db3896653e04d8c3c0c1b1b 100644
--- a/tests/js/polyfills/runtime.polyfill.test.js
+++ b/tests/js/polyfills/runtime.polyfill.test.js
@@ -105,3 +105,8 @@ QUnit.test('getPlatformInfo gets info', function (assert) {
 QUnit.test('getPackageDirectoryEntry not implemented', function(assert) {
   assert.throws(chrome.runtime.getPackageDirectoryEntry, 'not implemented');
 });
+
+// Test that id is null.
+QUnit.test('id correct', function(assert) {
+  assert.strictEqual(chrome.runtime.id, null);
+});