MSSQL seems to support limits for decimal type, so we add a default
limit.

Merge branch 'querybuilder-dynamic-column-types' of github.com:cebe/yii2 into querybuilder-dynamic-column-types

* 'querybuilder-dynamic-column-types' of github.com:cebe/yii2:
  Added phpdoc about precision constraints for abstract db types

Feature was requested in yiisoft/yii#765

fixes #465

\yii\widgets\Menu improvement

[ready]bootstrap tabs widget

[ready]added button group dropdowns

[READY] jQuery UI tabs rework

[ready]added progress widget

[READY] jQuery UI resizeable widget

[READY] jQuery UI draggable widget

[READY] jQuery UI droppable widget

[READY] jQuery UI selectable widget

[READY] jQuery UI spinner widget