- Removed dual_noise_demo example as it was deemed unnecessary.
- Added perlin_demo example for visualizing Perlin noise.
- Updated biome_demo to generate SVG visualizations of tilemaps.
- Changed biome properties from thresholds to ratios for better control.
- Modified terrain generation logic to accommodate new biome properties.
- Improved documentation with detailed API and usage examples.
Signed-off-by: szdytom <szdytom@qq.com>
