Jar 包运行时皮肤目录名问题

打包成jar时，获取的皮肤路径的目录名包含/，导致匹配错误
```java
for (final Iterator<Path> it = walk.iterator(); it.hasNext(); ) {
  final Path file = it.next().getFileName();
  final String fileName = file.toString(); //此处取的的fileName是含/的，如 Bruce，获取到的是Bruce/ ，而非Bruce
  if (fileName.startsWith(".") || fileName.endsWith(".md") || "skins".equals(fileName)) {
     continue;
  }
  ret.add(fileName);
}
```