auto fill sorting colums in ActiveDataProvider if none are configured
Lazy fallback of label creation for Sort class
Refactor DataColum to use model label for sorting link
DataColumn: Allow setting label of sort link via short syntax

attribute:type:Header should also affect sort link
use `@inheritdoc` for ActiveDataProvider::setSort
Finished model generator.
added label option to Sort::link()
css fix.
introduced DataColumn::label property
typos in doc
Refactored DataColumn::renderHeaderCellContent()
Moved label for Sort::link() to html options
Blowfish cost must be in range 4…31, not 4…30

`generateSalt` parameter validation fix.
Merge pull request #817 from maximal/patch-1

Blowfish cost must be in range 4…31, not 4…30
Merge pull request #809 from cebe/autoconfig-sorting

Gridview and DataProviders: Autoconfig sorting
crud generator WIP
Fixes #820.
Fixes #811.
added Cache::exists() to check key existance in cache
cherry picked RedisCache and redis\Connection from redis WIP branch

commit in redis branch was:
0cd65e7496befb3c4aed86e47257103fea63d329