Exclude firefox.com by default

[mcandre]

The website firefox.com is responsible for authenticating Firefox accounts, so this domain should probably be whitelisted by default, as it requires JavaScript in order to function.

[barbaz]

NoScript supports browsers other than Firefox -

Supported browsers: Firefox, SeaMonkey, Tor Browser (where it is built-in).
Other browsers based on Gecko versions >= 45 might work, but are not tested.

If this can be made default only in Firefox, then this sounds like a good idea to me.