Beamer: Put extra header last in header

Beamer: Put extra header last in header

* lisp/org-beamer.el (org-beamer-amend-header): Put extra header
last in header.

Tassilo Horn writes:

> I'm doing a LaTeX beamer presentation with org.  The org doc starts with
> these lines:
>
> --8<---------------cut here---------------start------------->8---
> #+STARTUP: beamer
> #+LaTeX_CLASS: beamer
> #+TITLE: Implementieren, Integrieren, Installieren
> #+AUTHOR: Tassilo Horn
> #+EMAIL: horn@uni-koblenz.de
> #+LANGUAGE: de
> #+BEAMER_FRAME_LEVEL: 2
> #+LaTeX_CLASS_OPTIONS: [presentation]
> #+BEAMER_HEADER_EXTRA: \usetheme[secheader]{Boadilla} \institute{Universität Koblenz, IST}
> --8<---------------cut here---------------end--------------->8---
>
> In the presentation, the ä in Universität is printed as an A with a ~ on
> top, followed by a d'.  The reason is that the BEAMER_HEADER_EXTRA is
> put before the input encoding declaration.  To be clear, org produces a
> TeX file that starts with
>
> --8<---------------cut here---------------start------------->8---
> % Created 2010-07-06 Tue 08:57
> \documentclass[presentation]{beamer}
> \usetheme[secheader]{Boadilla} \institute{Universität Koblenz, IST}
> \usepackage[utf8]{inputenc}
> \usepackage[T1]{fontenc}
> --8<---------------cut here---------------end--------------->8---
>
> but it should be at least:
>
> --8<---------------cut here---------------start------------->8---
> % Created 2010-07-06 Tue 08:57
> \documentclass[presentation]{beamer}
> \usepackage[utf8]{inputenc}
> \usetheme[secheader]{Boadilla} \institute{Universität Koblenz, IST}
> \usepackage[T1]{fontenc}
> --8<---------------cut here---------------end--------------->8---
>
> In general, I'd say that it would be even more safe to put the extra
> headers below all default headers.