unification of meta-attributes handling:
* remove has_format, has_text_encoding, format, text_encoding methods on Entity
* remove rich_text_fields method on EntitySchema
* use instead has_metadata / meta_attribute on EntitySchema (from yams)
and attribute_metadata on Entity
# server debugging flag
DEBUG = False
# sqlite'stored procedures have to be registered at connexion opening time
SQL_CONNECT_HOOKS = {}
# add to this set relations which should have their add security checking done
# *BEFORE* adding the actual relation (done after by default)
BEFORE_ADD_RELATIONS = set(('owned_by',))
# add to this set relations which should have their add security checking done
# *at COMMIT TIME* (done after by default)
ON_COMMIT_ADD_RELATIONS = set(())
# available sources registry
SOURCE_TYPES = {}