On se base sur gettext, mais avec l'utilisation d'une langue par défaut qui sera obligatoire lors de la création de la chaine.

Behaviour changed for EmComponent and childs create method :
	- Takes care of duplicated names at creation
	- Handle all the checks in EmComponent method
Factorization of EmField.get_class_table() method
Added a @property method class_table_name to EmClass

Now an MlString instance is able to say if another MlString instance is equivalent using mlstr1 == mlstr2

Created the class Lodel.utils.mlstring.MlString needed by EditorialModel.lib.component.EmComponent
The first test pass ! =)