Add Json.toJSONValue & Json.fromJSONValue fix #1465
Add Json.toJSONValue & Json.fromJSONValue
fix #1465

Apply change from s-ludwig

chalucha/vibe.d,etcimon/vibe.d,gedaiu/vibe.d,Geod24/vibe.d,etcimon/vibe.d,rejectedsoftware/vibe.d