fix xiami bug

**the bug is string encode proplem. maybe it can not reproducing in other OS except windows.**


# environment #
**win7**
**Python 3.2.1 (default, Jul 10 2011, 21:51:15) [MSC v.1500 32 bit (Intel)] on win32**

# setup #
D:\mine\githubox>c:\Python32\python.exe you-get\you-get http://www.xiami.com/album/3332

# result #
  File "D:\mine\githubox\you-get\src\you_get\downloader\xiami.py", line 34, in x
iami_download_lyric
    x.write(lrc)
UnicodeEncodeError: 'gbk' codec can't encode character '\ufffd' in position 142:
 illegal multibyte sequence