clean up task watching when disabled
clean up task watching when disabled

when a task is disabled, the same computation done on a SIGINT (how many lines to jump
before printing and exiting) was not being done.  This fixes that, and
simplifies how that line count is communicated among the goroutines.

fixes #365

mjbrender/snap,sandlbn/snap,intelsdi-x/snap,lynxbat/foo,mkleina/snap,intelsdi-x/snap,mjbrender/snap,mkleina/snap,sandlbn/snap,lynxbat/foo