Support for Json?, and String? as the response in a RequestView

[carson-katri]

Currently, RequestView only supports Data? as a return type.

This enhancement is to allow Json? and String? as responses as well by adding more initializers:

RequestView(myRequest) { (data: Data?) in ... }
RequestView(myRequest) { (string: String?) in ... }
RequestView(myRequest) { (json: Json?) in ... }

[carson-katri]

Codable support is now available in RequestView #4
Json and String are stilled planned.

[carson-katri]

I'm pushing this to v1.3.0 because it requires more than implementing more initializers...

[carson-katri]

I'm pushing this again 😄 I want to tag 1.3.0 now so people can use the new error and timeout additions.