More dynamic register

* pwf registers always as global
Tests expect global pwf
[drop] Array.prototype.clone

* Dropped useless code
Object#merge -> pwf#merge

* It is not necessary to bind #merge to Object prototype, deprecate
Drop deprecated code

* Dropped Array.prototype#clone
* Dropped Object.merge (in favour of pwf#merge)
[fix] Tests for pwf#merge
Inline docs: pwf#merge
Inline docs: #has_touch, #register_as_global, #v