Properly support painting tiles from secondary tileset

Fix collision and elevation selections

Add multi-block and smart-path tile painting

Add ability to export map image

Add map grid toggling

Display hovered map tile and block info

Populate items, flags, and vars in dropdown menus

Support adding new maps

Fix map connections, warps, and map event saving

Since map constants can be inferred from map names, but not the other
way around, create a mapping between map constants and map names and use
that to find the connected map.

Fix songs and map obj gfx