[c++0x] <date_time> implementation, take 3

[Pedro Lamarão]

Paolo Carlini escreveu:
> Hi Pedro,
>> The test suite hasn't changed since take 2.
> ... but remember to use -std=gnu++0x in all the tests.
>
> Besides that, I think we are almost ready for the commit, only, please 
> double check the uglifications: I'm seeing locals with names such as 
> ns and xns in some operators... Also, as a largely stylistic issue, 
> please fully qualify std::time, std::time_t.
>
> Paolo.

Should I always fully qualify stuff from <cfoo> headers?

--
 P.