Visual C++ 2012 (Express) compile support

Added <memory> for shared_ptr and unique_ptr support in Visual C++ 2012.

Thanks to Brian-Cole for diagnosing this.

Fixes #99
Fixed: Dates before 1970 with time of midnight incorrectly inserted

This is especially onerous because the default time for a date is midnight.

Tests have been added to verify that dates with a time of midnight are
inserted and retrieved correctly.

Fixes #85
Fixes #103