METTLE Core update 1.4!

Some minor changes that should have a major impact:

• Offensive pools now depend on Nature instead of Poise again. After trying Poise out it felt a bit too overextended as an Attribute and didn't quite fit the Brave and Bold portrayal of pulp characters.
• Not having the right Focus defaults to double difficulty, not half dice. Halving the dice led to a nuisance advantage for people with odd leveled attributes and begged questions about whether bonuses or penalties should be halved too.
• Sample Adventure: self-edited a bit to be clearer.
• Sample adventure: removed suggestion that the Guide play spare castaways - the Guide has enough to do, it turns out.

Future plans include maybe some external editing or art, and re-upping the print version. On that note, someone actually asked me to put the print version back up. I'm floating a few inches about the floor right now - I had no idea anyone cared!