The me.json was not up to date (Models don't forward classtypes modifications to loaded json file)
Some bugfix on fieldtypes that was not used (because of old me.json)

The two new properties are :
 - superior_cls stores a LeObject child class
 - subordinate_cls stores a LeObject child class

Implements a utils method in _LeRel2Type to fetch a rel2type leapi class name given a superior and a subordinate

Begin to work on fieldtypes

Bugfixes in generated code imports
Enhancement on generated classes retrieval

Updated the _LeObject tests to use the dynamic code

LeRoot represents hierarchy root

Deleted the classinstancemethod decorator because of inheritance problems (not sure they were real...)
Add a shortcut method to LeFactory to get the generated LeObject class
+ bugfixes

Added a test on LeFactory generated code

LeFactory.generatePython() is a method that generate LeObject code and python classes for each EmClass and EmType in an EditorialModel