Conformance report for reference

[miloyip]

https://github.com/miloyip/nativejson-benchmark/blob/master/sample/conformance_Jansson%20(C).md

[phst]

Thanks. Some of the "parse string" and "roundtrip" ones can be fixed easily: https://github.com/miloyip/nativejson-benchmark/pull/97

The others are more difficult:

• The double parsing behavior is documented (https://jansson.readthedocs.io/en/latest/conformance.html#real-vs-integer), Jansson doesn't fall back to double on integer overflow. Maybe we could add a flag to do so.

• The double serialization issues are because Jansson doesn't always generate the shortest form when serializing doubles. It could be argued that that isn't even an error because the decimal strings represent the same IEEE 64-bit numbers.