Unit conversion definitions

All these definitions are in uint64_t.

Definitions:

#define QH_NS_PER_US

#define QH_US_PER_MS

#define QH_NS_PER_MS

#define QH_MS_PER_S

#define QH_US_PER_S

#define QH_NS_PER_S

#define QH_S_PER_MIN

#define QH_MS_PER_MIN

#define QH_US_PER_MIN

#define QH_NS_PER_MIN

#define QH_MINS_PER_HOUR

#define QH_S_PER_HOUR

#define QH_MS_PER_HOUR

#define QH_US_PER_HOUR

#define QH_NS_PER_HOUR

#define QH_HOURS_PER_DAY

#define QH_MINS_PER_DAY

#define QH_S_PER_DAY

#define QH_MS_PER_DAY

#define QH_US_PER_DAY

#define QH_NS_PER_DAY

#define QH_DAYS_PER_WEEK

#define QH_HOURS_PER_WEEK

#define QH_MINS_PER_WEEK

#define QH_S_PER_WEEK

#define QH_MS_PER_WEEK

#define QH_US_PER_WEEK

#define QH_NS_PER_WEEK