#2630: `yii\heplers\Html::url` moved to new `yii\helpers\Url::create`
Added Url::asset
Added Url::rememberReturnUrl
Added Url::canonical
Renamed methods, added Url::getHome
Added Url::createAbsolute, adjusted signiatures
Adjusted changelog
Argument for Url::base is now optional
Adjusted Url helper methods
Adjusted URL helper, fixed usage
Fixed recursion
Fixed inconsistent usage of getters
Fixed absolute URLs in Url::to
Removed passing unused parameter
Further adjustments for Url helper
Made $url default consistent
Moded URL management methods from controller to Url helper, updated docs
Added separate schema and absolute parameters
Combined $schema and $absolute into $schema
Added tests, final Url helper adjustments