Returns object from methods for chaining purpose

[arturf]

No description provided.

[samdark]

I'm not sure it's a good idea.

[samdark]

@yiisoft/core-developers opinions?

[klimov-paul]

Method setAttributes() produces a virtual property attributes, so usually its return value is never used.
Still we can return a self reference as a result. However, there are many similar 'setters' around the framework. There should be a consistency among them.

[SilverFire]

Agree with @klimov-paul

[samdark]

Since some setters return true/false depending on the result I don't think it's a good idea to return object instance for other cases.

[coveralls]

Changes Unknown when pulling 645d818 on arturf:imp-models into ** on yiisoft:master**.