Custom event variable, to know if checkbox was checked or unchecked

[Tessmore]

checklist-change event allows a custom function call, but you don't know if the user clicked the checkbox to "check" it or "uncheck" it. With this pull request you can.

I think #127 kind of wants this, but in the checklist-change-before function? Not entirely sure.

[beradrian]

For this you can use the checked scope variable or whatever you specify with ngModel. Check this out: http://jsfiddle.net/s3p9q6zj/