Added convinience constructors for PopupButton
Added convinience constructors for PopupButton

bogdan-voevoda/nimx,qqquinta/nimx,bogdan-voevoda/nimx,rrenderr/nimx,yglukhov/nimx,rrenderr/nimx,qqquinta/nimx,yglukhov/nimx,qqquinta/nimx,yglukhov/nimx,bogdan-voevoda/nimx,rrenderr/nimx