PanFengyun <pan_feng_yun@163.com>'s previous github id was @FengyunPan

Due to some problem with github, he lost access to @FengyunPan and
is not using @FengyunPan2. So let's switch over to the new id. Github
has promised to release the previous id back in 6 months, so we may
have to switch it back later.