Drop selector framework in Commons

[leonardofl]

The Selector framework in the Commons project was built to be resued in the NodeSelector classes and in the EasyESBNode selector classes. But now we have only node selector, and this separation makes code much more hard to understand. Moreover, this piece of the code is one of the biggest interest for researchers that may profit from EE.

Before refactoring: move tests from selector (commons) to node selector