`<AttachFile>`: `name` extension from `filename`

[pr-apes]

if and only if name includes no extension this is a way to avoid stupid mistakes

[pgundlach]

Not sure what this is supposed to do? What is the problem that can occur?

[pr-apes]

With the following code:

<AttachFile filename="invoice.xml" name="new-name"/>

the resulting attached document would be new-name instead of new-name.xml.

In that case, Acrobat would prevent even saving the file (I get an error message: Acrobat cannot export this file).

With the patch above, embedded filename would be new-name.xml.

This is the only part of #418 which can be used now.

[pr-apes]

Now I see that the title was wrong: it is not <PDFOptions>, but <AttachFile>.

Closing and providing a new pull request.