First two-week sprint.

I think that was kinda long to wait for a release. I might push those out sooner next time…

New features:

• Nicer animation when opening and closing tabs.

Fixes:

• Move new tabs to the top of the list. (Fixes #3.)
• Don't hide the toolbar in customize mode. (Fixes #168.)
• Fix scrolling to selected tab. (Fixes #245.)
• Don't show sidetabs on popups. (Fixes #135.)
• Fix the colours for light and dark themes. (Fixes #132.)