Update repository structure

.gitignore

 .eslintrc
-MEMO.md
 .DS_Store

README.md

 # WebGL Fluid Simulation Tutorial
 
 <div align="center">
-    <img src="./screenshot.jpg"></img>
+    <img src="./assets/screenshot.jpg"></img>
     <h4 align="center">WebGL2 Fluid Simulation Tutorial</h4>
     <p align="center">
         <img src="http://img.shields.io/badge/-WebGL2-990000?style=flat&logo=WebGL&link=https://github.com/htcrefactor/WebGL-Fluid-Simulation"/>

script.js

@@ -917,7 +917,7 @@ let bloomFramebuffers = [];
 let sunrays;
 let sunraysTemp;
 
-let ditheringTexture = createTextureAsync('LDR_LLL1_0.png');
+let ditheringTexture = createTextureAsync('./assets/LDR_LLL1_0.png');
 
 const blurProgram            = new Program(blurVertexShader, blurShader);
 const copyProgram            = new Program(baseVertexShader, copyShader);