* contrib/lisp/ox-deck.el (org-deck--build-meta-info): Use
`org-export-get-date'.
* contrib/lisp/ox-groff.el (org-groff--mt-head): Use
`org-export-get-date'.
* contrib/lisp/ox-koma-letter.el (org-koma-letter-template): Use
`org-export-get-date'.
* lisp/ox-latex.el (latex): Introduce new buffer keyword.
(org-latex-template): Use new keyword.
* lisp/ox-beamer.el (org-beamer-template): Use new keyword.
* lisp/org.el (org-create-formula--latex-header): Use new keyword.
* contrib/lisp/ox-koma-letter.el (org-koma-letter-template): Use new
keyword.
Previewing of LaTeX snippets takes account of LATEX_HEADER keywords.
LATEX_HEADER_EXTRA keyword allows to specify some header lines that
will not be used for building snippets.
* contrib/lisp/ox-koma-letter.el (org-koma-letter-template): Allow to
span documentclass options accross multiple lines in template.
* lisp/ox-beamer.el (org-beamer-template): Allow to span documentclass
options accross multiple lines in template.
* lisp/ox-latex.el (org-latex-template): Allow to span documentclass
options accross multiple lines in template.
Thanks to Michael Strey for reporting this bug.
* ox-koma-letter.el (org-koma-letter-template): rename
org-export-latex to org-latex for package lists.
These variable names were changed with the merge of the new exporter.