* Updated php.net link for some MemCache properties [skip ci]
* Changed protocol to https for links to php.net in comments
* Changed protocol to https for links to php.net in code
* Changed www.php.net (http) to secure.php.net (https) in comments
* Changed www.php.net (http) to secure.php.net (https) in code
* Changed protocol to https for links to php.net in UPGRADE.md
* Changed protocol to https for links to pecl.php.net in comments
* Changed us.php.net to secure.php.net (https) in comments
* Changed protocol to https for links to php.net in docs
* Changed www.php.net (http) to secure.php.net (https) in docs
* Changed protocol to https for links to pecl.php.net in docs
* Changed ru/jp.php.net to secure.php.net (https) in docs
Don't sure about russian guide: is this links meant to be for guide on russian, or not?
- Deprecated `yii\base\BaseObject::className()` in favor of native PHP syntax `::class`, which does not trigger autoloading
- Deprecated XCache and Zend data cache support as caching backends
- Deprecated `yii\BaseYii::powered()` method
- Added `yii\base\InvalidArgumentException` and deprecated `yii\base\InvalidParamException`
- Added `yii\BaseYii::debug()` and deprecated `yii\BaseYii::trace()`
Added catch `\Throwable` to be compatible with PHP7.
Added it in cases where object state needs to be kept consistent.
Mainly on transactions but also some other places where some values are
reset before exiting.
Most of them could probably be refactored by using `finally` in 2.1, as
that requires PHP 5.5.
fixes#12619