Add namespace def. to Tubnil.
Add namespace def. to Tubnil Bright.
Fix up diff colors for Tubnil & Tubnil Bright.
Add Big Duo version of Tubnil color scheme.

Slightly lighter/pastel-ier version of Tubnil. Also, strings have
background colors. And there's yellow. And the background is lighter.

Also, some green is now purple. This is a thing.
Add note about Big Duo, rearrange section order.