Use http://tools.ietf.org/html/draft-kelly-json-hal-05 has base format.
Provide possibility to request instance, browse them and check their message
and connection parameters.

If SR is not correctly installed, slapgrid complained that "file already exists". This is misleading error.

Fix Interface serializing that was trying to serialize logger as well.

Code checking validity only works for ipv6. So we only return True.