D27583: rebuild mosaic multiple dataset

jjazeix added inline comments.

INLINE COMMENTS

> Data.qml:61
> +            ],
> +            "modelDisplayLayout": "singleColumnReduced",
> +            "images": images.slice(0,3)

why using the same variable for 2 differents use cases?
they are 2 different features, so let's separate them in two different variables.
If each time we add an option, we have to rename: modelDisplayLayout to singleColumnReducedNewFeatureAndAnotherOne and in the code do
if(modelDisplayLayout == "single..." || "single..." || ...) and somewhere else if(modelDisplayLayout == "...Reduced..." || ...) it is not readable or evolutive.

REPOSITORY
  R2 GCompris

BRANCH
  arcpatch-D27583

REVISION DETAIL
  https://phabricator.kde.org/D27583

To: dekumar, #gcompris_improvements, jjazeix, timotheegiet, echarruau
Cc: kde-edu, narvaez, apol