Inventory management

[kpreid]

To have a usable inventory we need:

• [ ] An inventory size bigger than just the “hotbar” itself.
• [ ] UI state where said entire inventory is visible.
• [ ] Interactions to rearrange, re-stack, and discard inventory items.
  • [ ] UI, rendering, and input-handling support for drag-and-drop type gestures.
    • [ ] Click-and-drag inputs (as opposed to only instantaneous response to mousedowns)
    • [ ] Non-critical: Grabbed item rendered floating above the UI off-grid
  • [ ] Non-critical: support for items dropped in the world (#301).
• [ ] For editing, a way to bootstrap into having various editing tools without necessarily having to keep the whole set in inventory. (I have been thinking that there should be a “free editing toolbox” that you can copy items out of, but that is even more mechanisms needed.)