[lunox-core] json should not be parsed as form data

[axmad386]

Current implementation of body parser is when request method is not get, everything is parsed via formidable. This will introduces incorrect behavior. For example request with method put but sent application/json it will threat single array as not array.

agent.put("/url").send({ids: ["randomid"]}) 
// body will parsed as 
{ ids: "randomid"} --> it should be {ids: ["randomid"]}