daemonization, io socket and file redirection

```
usage: ./bin/default.elf <tap interface> [-t <port>|-u] [-d] [-e] [-o]

Options:
-d      daeomize
-e      redirect stderr to file
-o      redirect stdout to file when not attached to socket
-u      redirect stdio to unix socket
-t      redirect stdio to tcp socket

The order of command line arguments matters.
```