Fixed Issue x-www-form-urlencoded

[antsankov]

This fixes a bug with the restful service attempting to unmarshal a x-www-form-urlencoded request like it is JSON in POST/PUT requests. This fix simply prevents umarshal from tampering with the request body and returning an error so it can be encoded further down the line using something like this.

I was considering doing the decoding using gorilla/schema to the payload in this PR like I'm doing in my program, but I don't know what the policy on external libraries is.