Adjusted #3305: `MigrateController::refreshSchema()` is no more called automatically
Fixes #4277: `yii\grid\GridView` is no longer throwing an exception in non-debug mode when results are empty and `columns` aren't defined
Fixes #6279: `yii\db\Schema::getLastInsertID()` was passing wrong default schema name to PDO
added missing `@since` annotations
Changed #4277 behavior
better fix for #5448 not using customized DateTime class

fixes #6263 and has no problem with PHP Bug:

> it is a PHP bug: https://bugs.php.net/bug.php?id=45543
> Fixed in this commit: php/php-src@22dba2f#diff-7b738accc3d60f74c259da18588ddc5dL2996
>
> Fixed in PHP >5.4.26 and >5.5.10. http://3v4l.org/mlZX7
Enh: `yii fixture` command now offers help if no arguments are provided instead of crashing
Fixes #5480: Added defensive code to `yii\web\User::getIdentity()` to avoid potential infinite recursion
Fixed doc [skip ci]
adjusted missing return for fix #6263
Reverted #3305
Fixes #6305: `yii\i18n\Formatter::asParagraphs()` was not unicode-aware
Update yii.php

Added relative time translations
fixed wrong CHANGELOG entries

introduced by @samdark in the following commits:

- c6b0e24a456d19092b47d9296fdd739b8899cded
- 7c5938f902553db6bd592040105e148f6a1470fd
- eaf8ece568cdb2be320006b0b202fa94284b9d98
Fixes #6311: Optimistic lock for ActiveRecord does not work as expected
Fixes #6318: Made widgets more error-tolerant and user-friendly when certain option values are null
suppress warning thrown by IntlDateFormatter::parse()

Works around PHP Bug https://bugs.php.net/bug.php?id=68528

fixes #5962
Update BaseActiveRecord.php

The exceptions thrown on error are db exceptions.
fix oci batchInsert
fix oci schema type errors
when oci creates ColumnSchema, it forgot to get column php type, and the implement of `extractColumnType` is incomplete, must add common used CLOB and BLOB type