Petrichor: Rain & Storms

Added

• Low mist, as it forms in real life. Rain falling into the cool air near the ground fills it with mist: thickest in a drizzle or a steady rain, thinner in a downpour, mostly swept away by a thunderstorm's wind. It gathers where the air stands still and damp - between the trees and up into the crowns of a forest, over water and swamps, in hollows and valleys - drifts in slow wisps and stays thin over open, high ground.
• After the rain the wet ground keeps breathing mist out: it lingers in the evening, at night and in the morning, and the sun burns it off by midday.
• New option rain.mist (1 by default, 0 turns the mist off).

Fixed

• The rain's haze no longer fades out under trees: a forest canopy dims the sky light, and the mod took it for a roof.