NNP Fluidlogging

Took a more serious look at the thread safety issues with IBlockExtension#getLightEmission - looks like it's a problem accessing the chunks from a level context during worldgen. I've taken a slightly more nuanced approach to fixing it, and believe it's working much better now. I also added a config option - since this behavior has been problematic, and has a performance penalty, light from logged fluids is now disabled by default.

Added initial support for logging flowing fluids (fluids can flow into loggable blocks, and loggable blocks placed in flowing fluids will be logged with them). This is a work in progress, and is still very buggy and I wouldn't recommend using it for anything more than to see what's possible. This is a "stretch goal" and probably won't receive much love unless people start requesting it. This is not a vanilla behavior. Config controlled and disabled by default.

Tip: config options usually aren't retroactive. Disabling a feature that's already in-use can create minor bugs (eg, disabling fluid lighting, then draining a lavalogged block, will cause it to glow indefinitely).