Fixes #3564: Fixed the bug that primary key columns should not take default values from schema
Merge branch 'master' of git://github.com/yiisoft/yii2
Tabs to spaces to be consistent

```
vendor/bin/indent --spaces -r framework/
vendor/bin/indent --tabs -r . --pattern=*.json
vendor/bin/indent --spaces -r . --pattern=*.md
vendor/bin/indent --spaces -r . --pattern=yii.*.js
vendor/bin/indent --spaces -r . --pattern=*.css
```
#3521: Added `yii\filters\HttpCache::sessionCacheLimiter`
RangeValidator typo fix
improved docs about application and module namespace

fixes #3539
fixed wrong usage of @see
another @see
Merge pull request #3569 from creocoder/range-validator-typo-fix

RangeValidator typo fix
Fixes #3284: Added support for checking multiple ETags by `yii\filters\HttpCache`.
Updated pt-BR translation
Merge pull request #3571 from leandrogehlen/master

[ci skip] Updated pt-BR translation
SQLite support for disable integrity check

This is a porting from yii framework version 1.
I need it to run functional tests with fixtures.
Changelog updated
Merge pull request #3544 from MDMunir/patch-1

Add $key to function parameter
updated upgrade info [skip ci]
Fixes #3542: Removed requirement to specify `extensions` in application config
Fixed changelog
Merge branch 'zeeke-patch-1'
Merge branch 'origin/master'