0.10.1: Activation improvements

This release adds and improves the methods of activating the extension on articles:

• There's now an automatic popup message on cluttered articles. Click it to easily enable the extension.
• Or right-click any link and select "Open Link with Unclutter".
• The automatic activation feature per domain has been simplified, and the settings page for it has been redesigned. Domains aren't added to the allowlist by default now.

Thank you to everyone who suggested these features!