add concept-autoloading.md -wip
Merge pull request #4101 from qiansen1386/patch-10

fix duplicated white space and typo [skip ci]
Reverted #4098.
Fallback at `Security::generateRandomKey()` removed
Doc comments at `Security::generateRandomKey()` adjusted
Merge remote-tracking branch 'upstream/master' into upstream

* upstream/master:
  Reverted #4098.
  fix duplicated white space and typo [skip ci]
  typo fix
  Fixes #4098: `yii\db\Query::addSelect()` should include `*` when it is called the first time
add concept-autoloading.md
translated properties
Merge pull request #4102 from yii2-chinesization/master

Chinese Translation for this week
Merge pull request #4089 from klimov-paul/87-security-component-3

Fix #87: security helper converted into component and improved
Fixes #4072: `\yii\rbac\PhpManager` adjustments

- Data is now stored in three separate files for items, assignments and rules. File format is simpler.
- Removed `authFile`. Added `itemsFile`, `assignmentsFile` and `rulesFile`.
- `createdAt` and `updatedAt` are now properly filled with corresponding file modification time.
- `save()` and `load()` are now protected instead of public.
- Added unit test for saving and loading data.
Merge branch 'master' into rbac-phpmanager-adjusment

Conflicts:
	framework/UPGRADE.md
Update BaseMessage.php

See https://github.com/yiisoft/yii2/commit/0ff0f9d32eb71cc13b7c6eea45f85d115f98a633

https://github.com/yiisoft/yii2/issues/4071
Merge pull request #4107 from SDKiller/patch-2

Update BaseMessage.php
Fixes #4103
fix links and format [skip ci]
fix wrong file name [skip ci]
Fixed a call of function "generateRandomKey()" in app\base\Security
Merge pull request #4108 from fps01/master

Fixed a call of function "generateRandomKey()" in app\base\Security
Merge pull request #4092 from dizews/afterUpdate_event_ench

changedAttributes of AfterSaveEvent contain an old values