Change validators from 'length' to 'string'

fixes #562

Add spaceless widget.

This reverts commit 9a5ca995.

Html helper pure HTML 5 mode without support old standarts

Model::formName() and ActiveRecord::getNamespacedClass() PHP 5.3 way

Removed composer.lock from all apps. Currently it creates more problems since framework code changes rapidly.

Improve application speed by using classMap for autoloader

Implemented Request::getAcceptedContentTypes().

This reverts commit 9d7597d6, reversing
changes made to 6b6390f7.

implementation of Response tied to actions

Renamed some folders to fit changed app structure.

Result of a discussion with @qiangxue
- there is not global Yii::$app->response anymore, every action has
  dedicated response class
- implementation allows using HMVC pattern now, nested actions do not
  interfer