A very simple wrapper around the iOS keychain.
First instantiate KeychainWrapper, then use the instance to create, read or delete keychain entries, e.g.:
let keychainWrapper = KeychainWrapper(service: "myApp")
// store password <-> username mapping for service "myApp"
keychainWrapper["username"] = "secretPassword"
// retrieve password for username
let password = keychainWrapper["username"]
// delete password entry for username in service "myApp"
keychainWrapper["username"] = nilSee LICENSE.md.