An example of how to use the API for a DHT based name registration service.

I think there's an issue with the .dylib, can't use the constant
`Ed25519.SEED_SIZE` I immediatly get an unsatisfied link error.
(However, I can create a session, I see the messages coming in from UPnp, NatPMP, DHT)

```
Exception in thread "main" java.lang.UnsatisfiedLinkError: com.frostwire.jlibtorrent.swig.libtorrent_jni.ed25519_seed_size_get()I
	  at com.frostwire.jlibtorrent.swig.libtorrent_jni.ed25519_seed_size_get(Native Method)
	  at com.frostwire.jlibtorrent.swig.ed25519.<clinit>(ed25519.java:66)
	  at com.frostwire.jlibtorrent.Ed25519.<clinit>(Ed25519.java:12)
	  at com.frostwire.jlibtorrent.demo.DhtNs.getDHTKey(DhtNs.java:124)
	  at com.frostwire.jlibtorrent.demo.DhtNs.registerName(DhtNs.java:55)
	  at com.frostwire.jlibtorrent.demo.DhtNs.main(DhtNs.java:101)
	  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	  at java.lang.reflect.Method.invoke(Method.java:483)
	  at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134)
```