Bug 568341 - [Model2Doc][Docx] Model2Doc must provide the framework to

generate a Microsoft Word docx file from a Document Structure model

* generate picture from diagrams
** update models to be able to select the image format
** update mapper to take the new attribut into account
** update transcription to generate picture

Signed-off-by: Pauline DEVILLE <pauline.deville@cea.fr>
Change-Id: I39211ad1568aa53bea121b6b7d70f9ec723ae191