posix_time's no longer boost::serialize between boost v1.64 and v1.65, 1.66

[jdmairs]

It appears that

4543: fix ptime 2038 issue

has changed the behavior of boost::serialization. My archives (built with boost 1.64) using boost::serialization (inherently using time_serialization.hpp) no longer load because the hours, minutes, etc fields are now 8 bytes instead of 4 bytes.

I'm using VS2017 15.4 and 15.2

[jeking3]

Yes, this is caused by #35. I'm looking into it. Boost.Serialization has versioning capabilities that could allow for compatibility, except that 1.65 an 1.66 will be writing the same version, so it's now "a mess".