Fix System Command plugin
Fix System Command plugin

1. Fix error code handle for 39191a55187a36141bff42fcaf803135c0fe0b3c
2. use WPF MessageBox
3. Fix postion / window handle for
39191a55187a36141bff42fcaf803135c0fe0b3c

qianlifeng/Wox,qianlifeng/Wox,qianlifeng/Wox,lances101/Wox,Wox-launcher/Wox,Wox-launcher/Wox,lances101/Wox