Resolve "Error handling on send"

Closes #9 (closed)

fixtures/config-invalid.json

 {
-  "api": "https://example.backbone.com/api",
+  "api": "https://example.backbone.fake/api",
   "client_id": "invalid-client-id",
   "client_name": "InvalidClientName",
   "subscription": "dot.delimited.topic.subscription.#",

fixtures/config-valid.json

 {
-  "api": "https://example.backbone.com/api",
+  "api": "https://example.backbone.fake/api",
   "client_id": "unique-client-id",
   "client_name": "UniqueClientName",
   "subscription": "dot.delimited.topic.subscription.#",