Changes

• CtapHid.handle doesn't accept a reference to a Auth struct anymore and now either returns nil or a struct { cmd: Cmd, cid: Cid, data: []const u8 } where cmd is the received command, cid is the channel id, and data is the data related to the command (e.g. cbor encoded CTAP2 command). This allows you to act on specific CTAPHID commands. You can call iterator() on the returned struct.
• Auth.handle now expects two arguments. The first is a pointer to a array of 7609 bytes (the max msg size of CTAPHID); this will probably change in the future. The second argument is the CBOR command. The Auth.handle function will write its response to the struct and then return a slice with the message. The slice references the array.

For an overview on how to use the new API, see README.md.