Refine downs-only setting

[revuluri]

As a solver, I’d like a “start in downs-only” setting that doesn’t need to be immediately overridden when it doesn’t make sense, such as:

• Puzzles tagged as word-ladder
• Puzzles tagged as cryptic
• Puzzles with unchecked squares

Personally I think it’s fine to replace the existing “downs-only” setting but this could also be an alternative instead.

[mdirolf]

So the idea is that those types of puzzles would just ignore the downs-only setting?