Common reorg (#8025)

* Re-organize common folder

* fix: Correct paths in tests

* fix: move new content to proper folder

* chore: Move audio folder to assets

* Move sprites to sprites assets directory

* Move css sprites to assets directory

* Split out readmes for common code and sprites

* Move images to assets directory

* Move destinatin of shared browserified file

* remove unused file

* move compiled js to client-old

* Fix karma tests

* fix: Correct paths for sprites

website/common/script/libs/errors.js

@@ -0,0 +1,42 @@
+import extendableBuiltin from './extendableBuiltin';
+
+// Base class for custom application errors
+// It extends Error and capture the stack trace
+export class CustomError extends extendableBuiltin(Error) {
+  constructor () {
+    super();
+
+    if (Error.captureStackTrace) {
+      Error.captureStackTrace(this, this.constructor);
+    }
+  }
+}
+
+// We specify an httpCode for all errors so that they can be used in the API too
+
+export class NotAuthorized extends CustomError {
+  constructor (customMessage) {
+    super();
+    this.name = this.constructor.name;
+    this.httpCode = 401;
+    this.message = customMessage || 'Not authorized.';
+  }
+}
+
+export class BadRequest extends CustomError {
+  constructor (customMessage) {
+    super();
+    this.name = this.constructor.name;
+    this.httpCode = 400;
+    this.message = customMessage || 'Bad request.';
+  }
+}
+
+export class NotFound extends CustomError {
+  constructor (customMessage) {
+    super();
+    this.name = this.constructor.name;
+    this.httpCode = 404;
+    this.message = customMessage || 'Not found.';
+  }
+}