Add comment.  Use clearer method for checking the time, because negative time intervals are annoying.  Make sure the currentTask ivar is cleaned up in -terminate.
Add comment.  Use clearer method for checking the time, because negative time intervals are annoying.  Make sure the currentTask ivar is cleaned up in -terminate.

JackieXie168/skim,JackieXie168/skim,JackieXie168/skim,JackieXie168/skim,JackieXie168/skim