Select a proper http client for iOS

[edeckers]

Currently the Blob Courier generates multipart http requests manually, which causes unnecessary complexity and bugs (#83, #86) and requires extra testing.

Select an Android OkHttp-equivalent for iOS and refactor the code. Requirements for the http client:

• Must handle multipart requests
• Must be lightweight
• Must be maintained

Any suggestions are welcome!

Candidates

• Alamofire