Internal cancel return type tweak and deletion of unused code
Spec tweaks for erlcron:cancel/1
Merge pull request #26 from synlay/feature/erlcron_cancel_fix

Wrong return type for ecrn_control:internal_cancel/1
Improvement: no longer need to see 'between' when you want the cron job to last all day.
Merge branch 'master' of github.com:erlware/erlcron