* user/clock.t: Refactored rtems_clock_get into 5 methods which
are single purpose and more strongly typed. They are:
rtems_clock_get_tod - Get TOD in Classic API structure
rtems_clock_get_tod_timeval - Get TOD in struct timeval
rtems_clock_get_seconds_since_epoch - Get TOD as seconds since 1988
rtems_clock_get_ticks_since_boot - Get ticks since boot
rtems_clock_get_ticks_per_second - Get ticks per second