initial support for JSONB - this only allows you to define the JSONB
datatype - this does not add any of the additional support for
querying/indexing yet.
and tests for JSONB - as this is a superset of JSON i've subclassed
the JSON tests as all of these should be applicable as well.
add has_key & contains operators for jsonb (ported over from hstore)
minor cleanup of the jsonb - had extraneous operators that where copied
from hstore that don't apply.

Add tests for ? and @> operators.
it's OK to pass a dict in - it does the right thing, no need to quote it
in the tests.
jsonb support for <@, ?| and ?& added.

need to see if equality already works.
Merge pull request #101 from ddimmich/master

Postgres 9.4 Jsonb support