* Support IPv6 addresses.
* Support updating addresses that aren't the client's own addresses.
* Set status to 'failed' if the update fails for any reason.
* Don't skip hosts if a previous update failed.
* Check for a non-OK code from the update server.
* Strip headers before processing responses.
This still uses API v1 because API v2 currently has some limitations;
see #180 for details.
Fixes#180
This makes it easier to package ddclient, especially as enhancements
are made such as unit tests or a man page.
I chose GNU Autoconf and Automake mostly because I'm familiar with
them, but also because I know they are well supported. Unfortunately
they can be difficult to understand/maintain (especially Autoconf), so
we may want to convert to something else later.
Addresses #146, #147
