Add Vietnamese into messages.

#2936: New favicon for applications

Fixes #2932: Added `yii\web\ViewAction` that allow you to render views based on GET parameter

See this for more details: https://github.com/yiisoft/yii/pull/3300

Tiny Change - Typo

Second Example should start with ProgressBar::begin not ProgressBar::widget

use alias format for table names

Refactored ActiveRecord::find() so that find(null) will also return an ActiveRecord instance instead of ActiveQuery.

Fixed phpdoc, removed unit tests for Formatter asRelativeTime that were relative to current time since it was impossible to specify correct expected values

Fixes #2911: Removed `tbl_` default for table prefix

Refactor errorhandler