[Refactorings] Improve the management of forbiden selectors

[jecisc]

We already have some refactorings that take care of not generating dangerous methods. For example, the "Generate accessors" will not generate a #name method on the class side, but a #name1 method instead.

I see some improvements to do:

• When we generate a method with a number in the name, we should leave a comment inside explaining why this is happening
• We should do those check in all refactorings generating methods

For the second point, for example I broke the image of a poor intern by using "Move to class side" on a method called "name".

Might interest @Ducasse and @AlexisCnockaert