WIP: Work on two stage sliding panel

As shown in the mockups below, a two stage sliding panel would involve having the initial top down swipe showing pinned actions. A second swipe would then show the full set of actions.

Other visual changes that are possible:

• For the light theme, lighten the background rather than darken it
• Have the sliding panel use the full width of the screen rather than having margins with a phone layout
• Remove the background panel for notifications as the background is already contrasting
• Avoid the delay when closing the panel and then immediately opening (you currently have to wait a few seconds)

I'm not sure if I have much time to tackle this right now because of school, but I think it would be a nice feature to have eventually.