void Invaders::killEdgeEntities() {
EntityVector entities;
for (EntityVector::iterator j = mEntities.begin(); j != mEntities.end(); j++) {
    Entity *entity = *j;
    //  * Dödsgränser *
    // Vänster:
    if (entity->getPosition().getX() < -20) {
        delete entity;
    }
    // Höger:
    if (entity->getPosition().getX() > VGCDisplay::getWidth() + 20) {
        delete entity;
    }
    // Upp:
    if (entity->getPosition().getY() < -80) {
        delete entity;
    }
    // Ner:
    if (entity->getPosition().getY() >  VGCDisplay::getHeight() + 20) {
        delete entity;
    }

}
mEntities = entities;
}