Set default water colours in greyscale mode in case the theme does not define them, decrement piano weapon on use

Set CurrentAmmoGear on piano (should fix notes again). Also disable focus on current hog if unplaced.

Add missing grayscale conversions

Spread flakes out over 5 layers now (far back, mid distance, just behind land, just in front of lands and hog, near distance). Spread clouds out over 3 layers (far back, mid distance, just behind land). Add a flatten clouds option, use d on Underwater. Alter some flake PNGs to reduce variation in size since scaling is being used.