Remove RemoveAccountDialog
AccountDialog: Apply the banner after cropping it
PixbufButton: Only scale the background image
AvatarBannerWidget: Also show a crop dialog for the avatar
CropWidget: Correctly set the initial selection rect
CropWidget: (Re)Set cursors correctly
AccountDialog: Add cancel button
ImageCropDialog: add cancel button
AvatarBannerWidget: Invoke the changed signals
AccountDialog: Set old_user_name