Add seed hiding controlled by cmd line option

[flend]

Adds a --hide-seed command line option that hides the seed display when playing. This is used in web-brogue where seeds are obscured to players until the end of game to avoid players trivially practising the same seed offline.

[tmewett]

What's the wider rationale for this? web-brogue seed tournaments?

[flend]

What's the wider rationale for this? web-brogue seed tournaments?

I got feedback that an exploit that people were uncomfortable with was that you could start a random-seeded game online, check the seed, play the same seed offline a few times and then return to the online game. This is relevant if people are competing for masteries or longest streak (see recent posts on brogueforum). I don't consider it particularly important, but it felt like a general good practice to make this non-trivial to achieve.

This is part of the patch set that goes onto CE for web-brogue and I'm always keen to reduce the patch set if I can mainstream features.

[tmewett]

Makes sense to me, thanks!