Improve speed of generating fog weather condition.

[chessmasterhong]

Current method of generating fog is very slow. Due to the implementation of the algorithm in the plugin, generating and maintaining the fog is computationally heavy to compute and draw to canvas.

This is due to the block size, which affects how many blocks are being drawn to canvas. Smaller block size results in greater amounts of blocks being drawn. Each block requires the algorithm to run once, coupled with the need to fill every visible area in the canvas yields a very slow and inefficient implementation.

Future plans are to either:

1. replace current algorithm with faster one
2. keep current algorithm and improve method of drawing blocks to canvas