Add a config file support

[badcrc]

For adding hosts without restarting the script.

It reads a list of hosts from a file in every execution so you can have the daemon running all the time and just add or remove new hosts.

[tinuzz]

Hi,

Can you make it so that the config file can be specified on the command line, and one doesn't have to change the script to use (or not use) a config file?

The easiest solution (albeit a bit ugly) would probably be to check the first character of the first argument, and if it's a '/', treat it as a file. Or do it like cURL, and treat names that start with a character like '@' as a file (stripping the @, of course). Both solutions would be acceptable to me.

Thanks for contributing, I appreciate it!

Best regards,
Martijn.

[tinuzz]

Or....

Add a note about the config file in the 'Configuration' section of the README.

But as it currently is, it uses a config file by default, and throws an exception if the file doesn't exist. Maybe change the default to None?

Best regards,
Martijn.

[badcrc]

Hmm I can check if the argument is a file/path or a host/hosts list.