return value would not be a valid array when json encoded after unlink().

fixes #6065

fixes #4745

groovy is now always on in ES 1.3.0

fixes #5662

Fixes #5799: `yii\bootstrap\ButtonGroup::buttons` can take all options that are supported by `yii\bootstrap\Button`

Pass all the button's config array to Button::widget() instead of creating new one item by item. Now allowed to pass in ButtonGroup button's configs any possible attributes(like tagName, encodeLabel, etc).

Fixed `yii\sphinx\QueryBuilder` does not support comparison operators (>,<,>= etc) in where specification

Fixes #5735: Added `yii\bootstrap\Tabs::renderTabContent` to support manually rendering tab contents

Fixes #5708

Revert "Fixes #3760: Gii model generator now imports classes when necessary instead of using fully qualified class names"

This reverts commit 0c8faedd.

Fixes #3760: Gii model generator now imports classes when necessary instead of using fully qualified class names

Fixes #5570: `yii\bootstrap\Tabs` would throw an exception if `content` is not set for one of its `items`
Fixes #5572.

Fixes #5587: `json_encode` is now used with `JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE` where it makes sense, also it is now default for `Json::encode()`

Fixes #5402: Debugger was not loading when there were closures, resources or PDO instances in the logged data

fixes #5623

fixes #5601