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.

default format is text in short format so it should also be
like that in array() defintion.