Added Firefox/extension Options page for:Ask rename for single file
Ask rename for multiple files
Notification timeout, default 5 seconds

Added storage permission so settings can be saved.
Single-file upload now checks whether ZIP is actually smaller; if not, it uploads the original file.
Upload notification now shows saved size and saved percentage.
ZIP entries use compression only when useful; otherwise file data is stored uncompressed inside the ZIP.
Button text is now rainbow colored, with red P in ZIP.
Toast notifications no longer block Gmail’s uploaded-file remove/cross button.