fixes #822

fixes #811

commit in redis branch was:
0cd65e74

Gridview and DataProviders: Autoconfig sorting

Blowfish cost must be in range 4…31, not 4…30

`generateSalt` parameter validation fix.

attribute:type:Header should also affect sort link

* 'master' of github.com:yiisoft/yii2:
  set default format for gridview to text

correct creation of new Sort object if none is there

set default format for gridview to text

use milliseconds only and fall back to seconds for older memcache
versions.