v0.1.0

First version.

• Folder tree in the Media Library (grid and list) and in every media modal.
• Files from subfolders visible in parent folders (per-user switch, site default
  in Media → Folder settings), with a folder badge on each file.
• Breadcrumb, subfolder tiles and a "files in subfolders" hint above the files.
• Drag and drop for files (move, ⌥/Alt to add) and folders; context menu on
  right-click; keyboard: arrows, F2, Delete.
• Undo (⌘Z / Ctrl+Z and snackbar) for every reversible change.
• Shift / Cmd-click range selection in the grid.
• Uploads filed into the open folder, stamped at drop time.
• Delete-folder dialog: move files up, to another folder, or delete them.
• No flicker when switching folders: the next page loads before it replaces
  the current one.
• HappyFiles import (settings button and WP-CLI), safe to repeat.
• Polish translation.
• Self-updates from GitHub releases on sites installed from the release zip.