Improves how types handle deserialization from string, including Option[T], seq[T], and Option[seq[T]]
Empty and null strings are no longer deserialized to 0, instead an error Result is returned
If an error occurs when parsing json, a JsonParseError is returned.
* Change parseJson to JsonNode.parse
Exporting `parseJson` causes symbol clashes in downstream repos that import std/json, so changing the signature completely avoid this clash.
* Fix usages of parseJson, update README