Add teaser/full option for syntax arguments

Very nice as is, but there is a small problem with image.filter sizes that are displayed.

When one does this: [image:1234 size=preview] things look very nice on a full page. However, the preview sized image is too big for a teaser and doesn't look right.

It would be great to have two values to each argument in the syntax like this: [image:1234 size=thumbnail,preview].

Ie: when there are two comma separated arguments, the first argument is used inside teasers, the second inside full nodes. This could also apply to the other options, class, style, etc, etc.