New bugfix release

This fixes an issue reported by @grahamc at:

NixOS/nixops#563

So it copes with the recent changes Hetzner made to their robot and also
provides a more helpful exception instead of just an AssertionError.

New bugfix release.

This fixes the issue reported by @fuzzy-id at:

NixOS/nixops#354

Basically, it updates the pinned certificate and now probes for the
system's CA bundle, so we shouldn't run into that issue again if Hetzner
changes their CA.

The CA that was changed was that of the Robot web interface, not the
API. But I'd expect the API cert to be changing very soon as well.

New bugfix release.

Fixes setting the password of an admin account, because the Robot now
uses a CSRF token.

Thanks to @rbvermaa for reporting the issue and doing extensive testing
of the fix.

New bugfix release.

Fixes the root CA certificate of the Hetzner robot.

Thanks to @Davorak for reporting.

New bugfix release.

This fixes encoding problems for the hetznerctl CLI.

Big thanks to @dangra for the initial fix, pull request (aszlig#7) and
testing. Also to @cyberplant for more input and testing.

New minor version.

This release consists of the following changes:

 - hetznerctl: Fix UnicodeEncodeError in server product name.
   (thanks to @haron for the temporary fix)
 - Support rebooting of vServers.
 - Server now has a new attribute is_vserver.
 - Add a README.md with examples.
   (thanks to @zoobab for bringing up the issue)

New minor version.

This release consists of the following changes:

 - Remove scraping of the Robot web interface for getting the server ID.
 - Display server number whenever appropriate.
 - Remove duplicate definition of exceptions.
 - Gracefully return if there are no subnets available.

New minor version.

Changes:

 - New subcommand "show" for hetznerctl which shows additional
   information about one or more servers.
 - Allow to get subnets of a specific server through the "subnets"
   attribute.
 - Allow te get IP addresses of a specific server through the "ips"
   attribute.

Small bugfix release.

Changes:

 - Don't include colons when generating passwords for admin logins.

New minor version.

This introduces the following changes:

 - Validate Robot's SSL server certificates (aszlig#2).
 - Admin accounts can new be managed with the "admin" property of a
   server instance.
 - Better and fixed up error reporting.