Millisecond resolution is possible and there are use cases for it
(automatic testing).

Seconds-based interface is preserved for compatibility.
Signed-off-by: NAri Kauppi <Ext-Ari.Kauppi@nokia.com>
Reviewed-by: NPhil Carmody <ext-phil.2.carmody@nokia.com>
Signed-off-by: NKevin Hilman <khilman@deeprootsystems.com>