Stub the method names on the bbcode element.
Update spec for the opening tags class

Stub the methods on object related to the subject,
instead of stubbing methods in the subject.
Update spec for the rules class

Stub the methods on object related to the subject, instead of stubbing methods on the subject.
Update spec for the attributes module

Use the new syntax for allowing methods with the arguments.
Cut down the relation between the closing tags & element classes

The closing tags class requires only names taken from the element object.
Add missing namespace for the opening tags class.
Use def delegator instead of the method in opening tags class.
Use struct instead of the initialization method in the opening tags class.
Refactored private interface of the opening tags class.
Move the readers, delegators and attributes into the private scope.
Move the method into the private scope.

It's not necessary to be visible.
Move the call of adding src to text into the process method.
Use def delegator instead of the method in the html element class.