Added support for storing (multiple) credentials consisting of username/password
Create server socket before forking instead polling until daemon is ready
Unlink socket only when daemon terminates

It's better to raise an exception in race conditions, instead silently unlinking
the socket in order to start the daemon again, and potentially overriding data.
Added a fallback for environments where UNIX domain sockets and/or fork() is not supported
Added config file
Merged the CLI and native messaging host into a single script