Regression on process_cpu_clock::timepoint io on V2

[viboes]

The following example #include <boost/chrono/chrono_io.hpp>

#define BOOST_CHRONO_PROVIDES_DEPRECATED_IO_SINCE_V2_0_0

int main() {
  std::cout<< boost::chrono::process_cpu_clock::now() << std::endl; 
}

outputs

{1383629724660000000;0;0} nanoseconds since process start-up

while if BOOST_CHRONO_PROVIDES_DEPRECATED_IO_SINCE_V2_0_0 is not defined, it outputs

1383629672240000000 nanoseconds since process start-up

A process_cpu_clock::duration::rep is a tuple like of 3 clocks real, user and system.

The same problem for input. V1 manages a format {v1,v2;v3} and is able to restore the 3 clocks, but V2 takes only the real clock in account.