nuker added to CONSTRUCTION_COST constant.ts

[rogerreeder]

Needs to be added to end.

declare var CONSTRUCTION_COST: {
    spawn: number;
    extension: number;
    road: number;
    constructedWall: number;
    rampart: number;
    link: number;
    storage: number;
    tower: number;
    observer: number;
    powerSpawn: number;
    extractor: number;
    lab: number;
    terminal: number;
    container: number;
    nuker: number;
};