Map editor: Allow tiles across multiple layers to be selected and pasted
Map editor: Provide layer panel instructions in status bar
Map editor: get tile selector showing tiles, and correctly share GL context
Add support for Dark Ages
Map editor: Draw arrows if the cell has movement flags set
Update Cosmo and Stryker full-screen image format name
Map editor: Share tile drawing code between map editor and tile selector

Also make the tile selector actually work for map editing.