Wrapper for Jack (Jack Audio Connection Kit) midi

Allows creating in/out ports, and registering callbacks of various types.

Callback name + argument list of callback function

- :process [client frames]
- :buffer-size-changed [client buffersize]
- :client-registered [client name]
- :client-unregistered [client name]
- :ports-connected [client port-name-1 port-name-2]
- :ports-disconnected [client port-name-1 port-name-2]
- :port-registered [client port-name]
- :port-unregistered [client port-name]
- :sample-rate-changed [client rate]
- :client-shutdown [client]
- :update-position [client state frame pos new-pos]

See [[register]]/[[unregister]], which work analogous
to [[add-watch!]] (idempotent, REPL safe, etc).

A Jack Transport leader that will set beat/bar/tick position information.

(def msg (byte-array 3 [130 64 100])) ;; Middle C on channel 2 with velocity 100

(channel msg)    ;; => 2
(event-type msg) ;; => :note-on
(note msg)       ;; => 64
(velocity msg)   ;; => 100

(event msg) ;; => [2 :note-on 64 100]

MIDI message parsing and construction logic.

Interpreting and constructing of midi message as byte arrays (signed) or long
arrays (unsigned).

``` clojure
(def msg (byte-array 3 [130 64 100])) ;; Middle C on channel 2 with velocity 100

(channel msg)    ;; => 2
(event-type msg) ;; => :note-on
(note msg)       ;; => 64
(velocity msg)   ;; => 100

(event msg) ;; => [2 :note-on 64 100]
```