Changes:
Fixes a bug that would leave the player's sky permanently white after two lightning strikes occur in rapid succession.
Adds ability to optionally specify the strength of a lightning strike (light, medium, heavy), with a default of "light".
Adds variation in the damage a player takes based on how close he is to the strike point.
- reduce chance of actual fire by 10.
- reduce chance of nodes getting modified
- adds a "dying flame" node that does not ignite
- lightning by default places the "dying flame"
- "dying flame" node destroys itself within a short period