Add trace syncing

This branch should be merge after !102 (merged)

Add two buttons :

• The first one make so that every render are in sync. Actually the mouse event that one receive is displayed to the others, that's all.

• The second one make so the displayed scale is the same for each render, the scaling is based one the first render (to improve if we want to scale based on a different render)

The scale button is better than before, now it scale by keeping the same center point. Thus you can center on entity in both renders and then scale, or the other way around. It was not possible before, because the center point was not kept.

This branch also fixes some bugs regarding multi-trace syncing. They were caused by some actions (pressing on no arrow/no event/vertical line) which only updated the first render instead of all.