title: How can I make Org-mode export to LaTeX with a specific preamble?
body: <p>When I do <kbd>C-c C-e l</kbd> to export an Org file to LaTeX it produces a document with a particular preamble. Instead of this particular preamble I would like it to use a preamble of my choice. Say that I want it to use the following preamble:</p>
  
  <pre class="lang-latex prettyprint-override"><code>% Don't forget to qpdf --linearize the final copy
  \RequirePackage[l2tabu,orthodox]{nag}% Old habits die hard. All the same, there are commands, classes and packages which are outdated and superseded. nag provides routines to warn the user about the use of those.
  \immediate\write18{sh ./vc}
  \input{vc}% Version control macros (for \VCDateISO in \date) http://www.ctan.org/pkg/vc
  \documentclass[a4paper,12pt]{article}% pt? doublepage?
  %\usepackage{geometry}
  \usepackage[utf8]{inputenc}
  \usepackage[T1]{fontenc}
  \usepackage{lmodern}% Latin Modern (derivate of Knuth's CM)
  \usepackage{fixltx2e}% \textsubscript and bugfixes for LaTeX
  \usepackage{microtype}
  \usepackage[strict=true]{csquotes}% Context-sensistive quotes. \enquote "" \enquote* ''. Use the integrated commands \textcquote and \blockcquote rather than biblatex internal commands to get contex sensistive quotes for them too. s/babel/autostyle in new version.
  \usepackage[bookmarks,pdfborder={0 0 0}]{hyperref}% links and pdfinfo. MUST BE LOADED LAST!
  
  \hypersetup{% Setup for hyperref
  pdftitle    = {[Title from #+TITLE]},
  pdfauthor   = {[Author from #+AUTHOR]}
  }
  </code></pre>
  
  <p>I know that you can manipulate which packages are used on a per file basis <a href="http://orgmode.org/manual/Header-and-sectioning.html#Header-and-sectioning" rel="noreferrer">as described in the manual</a> but I want this preamble to be used for all files unless ) specify otherwise. The preamble I want to use includes the following:</p>
  
  <ul>
  <li>deactivated packages (such as <code>geometry</code> above)</li>
  <li>packages loaded by <code>RequirePackage</code></li>
  <li><code>input</code> macros</li>
  <li><code>\immediate\write18</code> macros</li>
  <li>comments after <code>usepackage</code> macros</li>
  <li>a <code>hypersetup</code> macro that recognizes <code>#+TITLE</code> and <code>#+AUTHOR</code> from Org-mode files</li>
  </ul>