#383 remove showframe option of geometry package from preamble for preview

[Tilman]

When using the geometry package with the showframe option, previews of small math formulas result in complete pages being displayed next to the cursor because there are frames drawn around the page.

Please automatically remove the showframe option from the geometry package for previews.

Thanks,
Tilman

[Tim Hoffmann]

I don't think it's a perspective to automatically modify the preamble for previews. There are probably many changes one could want between the full document and the preview. It's not reasonable to hard-code them into the preview.

As an alternative we might add the option for a user-defined preamble, which might be used instead of the regular preamble.