Changes:

- The notification panel can hold a maximum of 5 notifications.
- Implemented "is-url" module (https://github.com/segmentio/is-url).
- New bookmark options button animation.

Added:

- Added black background color.
- Added Mail.ru search engine.
- Added update error notification info.

Fixes:

- Fixed developer debug console.
- Fixed bookmarks bar in fullscreen mode.