[Xwt.Wpf] Fix the license header and remove dead code
[Xwt.Wpf] Fix the license header and remove dead code

iainx/xwt,mono/xwt,cra0zy/xwt,antmicro/xwt,directhex/xwt,mminns/xwt,sevoku/xwt,akrisiun/xwt,TheBrainTech/xwt,mminns/xwt,steffenWi/xwt,lytico/xwt,hwthomas/xwt,residuum/xwt,hamekoz/xwt