Use sockaddr_storage instead of sockaddr

[mleiner]

This fixes the call of getpeername() and prevents an out-of-bound read.

This is done by providing a bigger buffer to getpeername()'s results.

It's a response to bug #168 and a new implementation of pull request 172.

Code compiles cleanly without warnings.

[sawolf]

Thanks for the patch! I don't have a great way to test IPv6 at the moment, but the change looks fairly straightforward.