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

fixes #6065

fixes #4745

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

Additional check added to `yiiunit\extensions\authclient\BaseClientTest::testNormalizeUserAttributes()`

Added ability to operate nested and complex attributes via `yii\authclient\BaseClient::normalizeUserAttributeMap`

feature is not reliable

fixes #5136

asArray will not include null valued keys

fixes #1311

issue #4687

- Removed `FileLoader` and used `\Twig_Loader_Filesystem` instead.
- Added support of Yii's aliases.
- Added `set()` that allows setting object properties.