Fix bugs with nested drawers in X.L.Drawer
Fix bugs with nested drawers in X.L.Drawer

There were two bugs:
1. The layout modifier assumed the rect's x was zero.
2. The layout modifier assumed that the stackset's focus actually had focus.

mathstuf/xmonad-contrib,mathstuf/xmonad-contrib,CaptainPatate/xmonad-contrib,f1u77y/xmonad-contrib,xmonad/xmonad-contrib,pjones/xmonad-test,ohlus/xmonad-contrib,0/xmonad-contrib,CaptainPatate/xmonad-contrib,0/xmonad-contrib,xmonad/xmonad-contrib,ohlus/xmonad-contrib,f1u77y/xmonad-contrib,CaptainPatate/xmonad-contrib,0/xmonad-contrib,mathstuf/xmonad-contrib,ohlus/xmonad-contrib