[json] fix json serialization for recent simplejson implementation, and test encoding of entities as with earlier simplejson implementation, iterencode internal stuff is a generated function, we can't anymore rely on the _iterencode overriding trick, so move on by stoping isinstance(Entity, dict). This is a much heavier change than expected but it was expected to be done at some point, so let's go that way.

[MESSAGES CONTROL]
disable-msg = C0301

[VARIABLES]
# Enable / disable this checker
enable-variables = yes
additional-builtins = _, display_name

[BASIC]
required-attributes=
attr-rgx = (w|[a-z_][a-z0-9_]{2,30})
variable-rgx = (w|[a-z_][a-z0-9_]{2,30})$
argument-rgx = (w|[a-z_][a-z0-9_]{2,30})$

[TYPECHECK]
generated-members=debug,info,notice,warning,error,critical,exception