Hello,

I was really surprised that headlines, that are so common in org-mode
are discarded by default in ox-koma-letter.

This patch tries to add the support for them.  It works for me but
requires some work to fit the coding and documentation convention that
are still unknown to me.

I will be happy to follow your suggestion or if somebody take this code
as a minimal implementation to start to work with.

Thanks in advance,
Daniele