Fix a small error
Store the typeName in the parent Type class : AbstractType
Propagate the typeName to the parent class
Initiate the new variables.

It includes the first set of variable hierarchy and the Memory object. (WIP)
Initiate a new typeConvertor.
update nested doctest in DomainFactory
update import of the Domain package
Merging domain and variable definition in Field's domain.
Add new tests and remove deleted VariableFactory from the doctest