Explicitly specify raw-loader for shader files

This helps standardize our Webpack config

src/ShaderManager.js

@@ -1,7 +1,7 @@
 const twgl = require('twgl.js');
 
-const vertexShaderText = require('./shaders/sprite.vert');
-const fragmentShaderText = require('./shaders/sprite.frag');
+const vertexShaderText = require('raw-loader!./shaders/sprite.vert');
+const fragmentShaderText = require('raw-loader!./shaders/sprite.frag');
 
 
 class ShaderManager {

webpack.config.js

@@ -25,10 +25,6 @@ const base = {
                 options: {
                     presets: ['es2015']
                 }
-            },
-            {
-                test: /\.(glsl|vs|fs|frag|vert)$/,
-                loader: 'raw-loader'
             }
         ]
     },