kill legacy code

__init__.py

 """cubicweb-email"""
 
-from cubicweb import ETYPE_NAME_MAP
-ETYPE_NAME_MAP['Emailpart'] = 'EmailPart'
-ETYPE_NAME_MAP['Emailthread'] = 'EmailThread'
-
-try:
-    from cubicweb.devtools import VIEW_VALIDATORS
-    VIEW_VALIDATORS['headers'] = None
-except ImportError:
-    pass