Spade edge event protocol

`request_handler/request_handler.go` is the primary work, it basically replaces our line printing with methods from the [spade portion of our protocol](https://github.com/TwitchScience/scoop_protocol/pull/5).

Note this commit also updates Godeps, so there is some noise in the diff.
I believe the string here has no effect; from:
http://golang.org/pkg/encoding/json/#Marshal

"The "string" option signals that a field is stored as JSON inside a JSON-encoded string. It applies only to fields of string, floating point, or integer types. This extra level of encoding is sometimes used when communicating with JavaScript programs:"

Since this is a []byte under the hood, I would bet it is just being base64 encoded.