Summer cleaning!

…Because that’s a thing, right?

• Fixed the “Open Link in New Window” menu item to actually do what it says
• Fixed opening target="_blank" links in a new window with Ctrl- or middle-click
• Updated the base color in menus and dialog windows from the default elementary slate-ish black to a new deep, dark blue-ish purple
• Tweaked the “Open Link Externally” dialog to better isolate protocols like mailto or tel
• Significantly cleaned up and reorganized the codebase to make future features and fixes easier
• Updated Dutch translations thanks to @Vistaus

Additional translations for new features will appear in future updates as translators have a chance to do their thing.

See all changes here: 5.1.1...5.2.0