Do not let page scrolling trigger zoom actions

[bartfeenstra]

Currently, when trying to scroll a page, and when doing so on a map or a tree, the map or tree is zoomed, rather than that the page scrolls. Considering both maps and trees are displayed at larger sizes, this greatly reduces the scrollable surface area, and causes frustration among users.

Definition of Done

• Do not allow scrolling to trigger map or tree zooming. Instead, require a modifier key, or multiple fingers.

[bartfeenstra]

This has now been fixed for the maps, but not yet for the trees. I haven't yet found a solution for Cytoscape. If #446 gets in soon, it might be worth fixing this for the new trees rather than the current Cytoscape trees.