KRACOEUS-7181:changed abstract attachment collection to be a table colle...

...ction to match updated mocks
it was working before, but currently the addLineActions don't override the defaults, so the cancel button on dialogs right now is calling a different method.  I tested the addAttachment by editing the html with firebug, i didn't think to test the cancel button in this way too.  i will have to look into this some more.