Fix json parsing for non numeric numbers (nan and inf)

This PR fixes #1893 by disabling ``QUOTE_NON_NUMERIC_NUMBERS`` for arrays' json generators and enabling ``ALLOW_NON_NUMERIC_NUMBERS `` for arrays' json parsers. Although this is documented to result in non-conformant json output I guess it is still OK as the json representations of collections are used internally (see http://wiki.fasterxml.com/JacksonFeaturesGenerator)
Asked @martint about this, and he's like it to stay legal JSON, so instead we should probably write it as ["nan"].