Removed base64 PNGs as they're no longer required.

Author: larz0

src/styles/brackets_scrollbars.less

@@ -57,15 +57,13 @@
      */
     :hover::-webkit-scrollbar-thumb:vertical,
     :focus::-webkit-scrollbar-thumb:vertical {
-        -webkit-border-image: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAkAAAAUCAYAAABf2RdVAAAABHNCSVQICAgIfAhkiAAAAAlwSFlzAAALEgAACxIB0t1+/AAAABV0RVh0Q3JlYXRpb24gVGltZQA0LzIzLzEyckCqugAAABx0RVh0U29mdHdhcmUAQWRvYmUgRmlyZXdvcmtzIENTNXG14zYAAACPSURBVCiR7ZIhDoNAEEXfkJCsxKBJimTPwA3mDHvqsXWrquqaIH5FKUk3XKAJT87789U3SQkYgZ5fNuABvDpgrLUOOefZzBYzW3LOc6112J/pgL6UMkZE+lZERCqlHO0m6WZmCydICuDencmWK/Tfoc3dn63YbxsAkpKkyd1XwD/eV0nT7jBJAO2Ej+kCvAFNxTqyZCNcEQAAAABJRU5ErkJggg==") 9 0;
         border-color: transparent;
         border-width: 9px 0;
         min-height: 20px;
     }
 
     :hover::-webkit-scrollbar-thumb:horizontal,
     :focus::-webkit-scrollbar-thumb:horizontal {
-        -webkit-border-image: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABQAAAAJCAYAAAAywQxIAAAABHNCSVQICAgIfAhkiAAAAAlwSFlzAAALEgAACxIB0t1+/AAAABV0RVh0Q3JlYXRpb24gVGltZQA0LzIzLzEyckCqugAAABx0RVh0U29mdHdhcmUAQWRvYmUgRmlyZXdvcmtzIENTNXG14zYAAACLSURBVCiRrdIxCgIxEEbhfxYFOyuxCCLazjGmTu6YKyRV7hFLCzshlcXCQoqxMWCd5B3gqx6pKgAcAJwA7NFfBVB2P+zsnLvGGI89kois3vtijAGp6sU5d+vFWsy85ZyfpKp3IuIRrKWqj2UG9N8CoFprP6MQM28NLCGE1wgqImtK6Q2g0uxtGjitL9E6N1T9Wl8CAAAAAElFTkSuQmCC") 0 9;
         border-color: transparent;
         border-width: 0 9px;
         min-width: 20px;