Begin to move all src javascript to es6. Add search/filter ignore case option.

src/_h5ai/public/js/lib/win.js

@@ -0,0 +1,23 @@
+const win = window; // eslint-disable-line no-undef
+
+if (typeof win !== 'object' || win.window !== win || !win.document) {
+    throw new Error('no-window');
+}
+
+const noBrowser = 'no-browser';
+const doc = win.document;
+const docEl = doc.documentElement;
+docEl.className = '';
+
+function assert(expr, hint) {
+    if (!expr) {
+        docEl.className = noBrowser;
+        throw new Error(`${noBrowser}: ${hint}`);
+    }
+}
+
+assert(!doc.getElementById(noBrowser), 'ie<10');
+assert(typeof Object.assign === 'function', 'assign');
+assert(typeof Promise === 'function', 'promise');
+
+module.exports = win;