Provide ability to set access control

[insha]

Currently I can't find this, but would like to have added to the wrapper to include the ability to create a new access control object that can take as input protection type and flags that are offered by the Keychain API.

Link to Apple Docs.

[suzukieng]

Agree, having support for access control would be handy. There are some nice usecases that are possible with iOS 8+, e.g. protecting a keychain item with TouchID. These are not just gimmicks but add real security, as the check is done on Secure Enclave.