So just using the great HTML5 video reproductor extension you can easily include videos on the gallery:
Instead of using a home made math expressions evaluator I moved to the GNU library libmatheval. This change imply more robustness and less maintenance.
Now I can improve the input-output layer (which needs a simple layer to create savers/loaders)
The code style modification has been completed (for sure style violations can be found, but at least it is not a complete disaster).
So I will consider it as the initial release, and start branching the work!