updating gpstime to allow pausing/resuming/stepping in time

• An aid for debugging user space programs that use gpstime.
• Adds ioctls to the gpstime drive to pause/resume/step
• Only works when system time is being used.
• Adds entries to sysfs to show state of the clock and to query/set the step size.
• Adds a utility program gps_module_utils which can pause/resume/step the time.

See issue #365 (closed)