ui: shortcuts not triggering actions

[robinroy03]

spacebar for play/pause not changing the icon of play/pause in player

zoom: mouse zoom on timeline isn't zooming the timeline

[draqist]

@robinroy03 can you explain the second point more, I fixed the first one

[robinroy03]

@draqist basically when i mouse-scroll on the timeline, it should zoom the timeline, now it isn't (like a normal zoom on timeline maps to zooming the timeline)