Merge branch 'master' of https://github.com/fluffrabbit/stb into work2

stb_perlin.h

@@ -78,6 +78,7 @@
 extern "C" {
 #endif
 extern float stb_perlin_noise3(float x, float y, float z, int x_wrap, int y_wrap, int z_wrap);
+extern float stb_perlin_noise3_seed(float x, float y, float z, int x_wrap, int y_wrap, int z_wrap, int seed);
 extern float stb_perlin_ridge_noise3(float x, float y, float z, float lacunarity, float gain, float offset, int octaves);
 extern float stb_perlin_fbm_noise3(float x, float y, float z, float lacunarity, float gain, int octaves);
 extern float stb_perlin_turbulence_noise3(float x, float y, float z, float lacunarity, float gain, int octaves);