Greasy Fork镜像

• Fixed some icon url getting error:
  • Use GM_xmlhttpRequest to fetch icon
  • Replace canvas image dealing with FileReader.prototype.readAsDataURL
• Replace old @license with standard license name
• Code quality improvement: use Promises instead of xhrs

修复潜在的bug

修复一个隐性小bug

修复iframe导致的icon获取错误