Initialization

int chkpt_init()
Initializes the checkpoint struct to allow other chkpt_* functions to perform their duties.

Arguments:	none, but it requires that the input parser be initialized so that it can open the checkpoint file.
Returns:	zero. Perhaps this will change some day.

int chkpt_close()
Closes the checkpoint file, frees memory, etc.

Arguments:	none, but chkpt_init must already have been called for this to work.
Returns:	zero. Perhaps this, too, will change one day.