[LyX/master] DocBook: implement svmult.

[Thibaut Cuvelier]

commit ebfdac4fa3c8b6eafab478cead48fc2667b9d2d3
Author: Thibaut Cuvelier <tcuvelier at lyx.org>
Date:   Mon Nov 2 03:44:51 2020 +0100

    DocBook: implement svmult.
    
    More generally, ensures that paragraphs in abstracts do not have something else configured.
    
    A major problem in making the layout more useful is that article titles are not supposed to be in TOC.

 autotests/export/docbook/Hollywood.lyx |  149 ++
 autotests/export/docbook/Hollywood.xml |   22 +
 autotests/export/docbook/svmult.lyx    | 3411 ++++++++++++++++++++++++++++++++
 development/autotests/invertedTests    |    2 +
 lib/layouts/svcommon.inc               |    9 +-
 lib/layouts/svmult.layout              |   10 +
 src/output_docbook.cpp                 |    9 +-
 7 files changed, 3608 insertions(+), 4 deletions(-)