Synopsis:

        task_sleep(tenths)

Arguments:

     tenths = The number of tenths of a second to put the task to sleep.

Description:    This function puts the calling task to sleep for the specified number of tenths of a second.        The function blocks during this time and will only wake up when the specified timeout expires.        

Returns Value:

Returns -1 if an invalid time is given (<0) otherwise returns empty string “” when timeout expires.