* upstream: (21 commits)
  Fixes #1643: Added default value for `Captcha::options`
  Fixes #1654: Fixed the issue that a new message source object is generated for every new message being translated
  Allow dash char in ActionColumn’s button names.
  Added SecurityTest.
  fixed functional test when enablePrettyUrl is false.
  fixed composer.json
  minor doc fix.
  Fixes #1634: Use masked CSRF tokens to prevent BREACH exploits
  Use better random CSRF token.
  GII unique indexes avoid autoIncrement columns
  updated debug retry params.
  Added sleep().
  Added unit test for ActiveRecord::updateAttributes().
  Fixes #1641: Added `BaseActiveRecord::updateAttributes()`
  Fixed #1504: Debug toolbar isn't loaded successfully in some environments when xdebug is enabled
  Mongo README.md updated.
  Fixes #1611: Added `BaseActiveRecord::markAttributeDirty()`
  Number validator was missing
  Fixes #1638: prevent table names from being enclosed within curly brackets twice.
  Unique indexes rules for single columns into array
  ...

Fixes #1654: Fixed the issue that a new message source object is generated for every new message being translated

GII generates rules for unique indexes

Number validator was missing

* upstream: (2012 commits)
  doc fix.
  Changed the signature of `urlCreator` and button creators for `yii\gridview\ActionColumn`
  parameter adjustment.
  The signature for `yii\gridview\ActionColumn::urlCreator` is changed - the `$action` parameter is moved to the first
  Fixed the signature of Schema::findUniqueIndexes().
  reverted #1598 and added a test for it
  Fix wrong array index in unique indexes for MySql
  Making accesors public
  Get DB unique indexes information
  Fixes #1610: `Html::activeCheckboxList()` and `Html::activeRadioList()` will submit an empty string if no checkbox/radio is selected
  Gii should keep horizontal layout
  Documentation at "yii\authclient" updated.
  Doc comments at "yii\authclient" updated.
  Auth clients "Choice" doc comments updated.
  Auth clients "Choice" widget javascript advanced.
  Bootstrap's dropdown encodes also trailing caret tag
  Auth clients "Choice" widget markup updated.
  Gii should keep horizontal layout
  extended from codeception testcase, added docs
  Auth clients for Facebook, GitHub, LinkedIn added.
  ...

Conflicts:
	framework/yii/helpers/BaseInflector.php
	tests/unit/framework/helpers/InflectorTest.php

The signature for `yii\gridview\ActionColumn::urlCreator` is changed - the `$action` parameter is moved to the first

Fix wrong array index in unique indexes for MySql

Get DB unique indexes information

Proposal for #66: auth client implementation