Bat Backpack and Fuel

[avescarelo]

In this modification, there is an item: Bat BackPack.
It gives a constant night vision effect, which is a very cheat functionality.
Please make it give this effect only if it is loaded with lava and water.

1 bucket lava (or any liquid) + 1 bucket water (or any liquid) = % min of night vision
or
1 bucket lava (or any liquid) = % min of night vision

Also make for this settings in config file.