Machine card bugfixes

Solves the problem that the css output of a style card is not updated when you add a css card to a subordinate skin card of the style card.

The technical details:
The output file gets updated when a card was changed that is listed in the +input card of the machine card.
We save in the input cards only the cards that actually contribute to the output
(because for example we don't want the item list of a skin card in the css file). 
But this means when you add a new css card to a skin card the output of the style card won't be updated because the skin card is the only card that hears about the change and it won't pass the information on to the style card because it's not listed in the style's input card.

Solution:
Put all involved cards in the input card and use for the output only the items that are non-pointer cards.
oof, not sure exactly what I was looking at when I wrote this comment.

I want to sit down and look at this event structure with you at some point.  Conceptually my first impression is that this should be in the "store" phase and not the "extend" phase, but if the API is not making it easy to follow the conceptual principles, then we need to bang on the api or the principles or ... something! ;)