Hey, so I discovered this module when I was trying to write my own pull-stream wrapper for net and was very happy, but not everything was working as I hoped. So I started changing and fixing some things as well as I could. I probably made a lot of mistakes so please forgive them.

Currently this adds

• Tests scripts are running and passing
• Use the previously commented "direct return" approach in client.js as this worked out very nicely in my tests
• Enable ipv6 & ipv4 support when dialing and listening
• Add a close method using pull-abortable to sockets created from handle.js
• Code style cleanup to use standard (I was a bit confused by the code style so please let me know if you want me to remove this/move to a different code style)

Currently the main issue I'm facing is that when I use the close method it's not closing properly the other side any tips on how to move forward would be appreciated.

A test suite testing these features and showing this problem can be found here: libp2p/js-libp2p-tcp#20 which needs the changes in this PR and afterwards can be run with npm test.