Support pointer and non-pointer for SetResult and SetError methods

[jeevatkm]

SetResult:

// Note: Result object can be pointer or non-pointer.
resty.R().SetResult(&AuthToken{})
// OR
resty.R().SetResult(AuthToken{})

// Accessing a result value
response.Result().(*AuthToken)

SetError:

// Note: Error object can be pointer or non-pointer.
resty.R().SetError(&AuthError{})
// OR
resty.R().SetError(AuthError{})

// Accessing a error value
response.Error().(*AuthError)

[jeevatkm]

Its done!