Guidance on certs and subdomain names
Remove suggestion of www-preview and www-dev

We don't want to encourage using the same wildcard certificate for
production, staging and development environments.
Fix meta-data and more descriptive name
Explicit advice against bad idea
Add hyphenated options back in

Hyphens in themselves are not a bad thing. We now have explicit advice
against using the same certificates in different environments.
Use root-relative URLs with .html suffix

I don't think this is strictly necessary, but it's what we're doing
elsewhere in the product. Homogeneity is sometimes a good thing.
Add 'Compliant' support for IE11 as it's released

Change message to just say IE7+ because it's an inevitability
that new ones will get added.
Move 'Compliant' support from Safari 5 to 7

Safari 5 is from 2010.
Add 'Compliant' support for iOS 7

It's got a decent enough proportion of users on it.
Typo: Blackberry -> BlackBerry