CardBook postulates to become a Thunderbird featured addon.

[Jörg Knobloch]

https://bugzilla.mozilla.org/show_bug.cgi?id=1336357#c11

(Aside: IMHO it is really a pity that this much work is being done 
without an attempt to make the addon code readable by others, nor 
following standard coding practices used in Mozilla. The code is also 
under GPL which is not compatible with Thunderbird. Collaboration, 
proper testing, proper documentation, MPL or more lenient licensing, are 
all part of making this usable as the default Thunderbird address book. 
These are not features that can just be tacked on at the end. So I just 
want to make it clear that this addon shows no sign of being on a path 
to replacing the default address book in Thunderbird. There is more to 
production code than just working.)

Jörg.