Merge branch 'master' of dev.yiisoft.com:yii2

Conflicts:
	framework/db/dao/Command.php
	framework/db/dao/Connection.php
	framework/db/dao/Query.php
	framework/db/dao/mysql/Schema.php
	tests/unit/data/config.php
	tests/unit/data/mysql.sql
	tests/unit/framework/db/dao/ConnectionTest.php

framework/db/dao/Connection.php

@@ -471,6 +471,11 @@ class Connection extends \yii\base\ApplicationComponent
 		}
 	}
 
+	public function getQueryBuilder()
+	{
+		return $this->getSchema()->getQueryBuilder();
+	}
+
 	/**
 	 * Returns the query builder for the current DB connection.
 	 * @return QueryBuilder the query builder for the current DB connection.