Default domain with or without www

[pbouda]

I think we need a default domain name for the known app when it is installed. Currently, the app will be available at the given domain and the same domain name with "www.". That causes some issues:

• All content is available under two domain names, so each page has two URLs. Both will be crawled and used by search engines and other sites to link to the content, which is not what one generally wants, I think.
• You can only use the Twitter connection with one of the domains when you post, as far as I understand. The app that you create on Twitter has one domain and one callback with this one domain.

I propose to have one single default domain or asks the user if he prefers to use the app with or without "www." before installation. The default for Wordpress is the domain without "www.", so we could set this as the standard. On the other hands there seem to be some concerns about "naked" domains (http://serverfault.com/questions/408017/why-does-heroku-warn-against-naked-domain-names), but I am not sure if that applies in our case.