Update for Node-4.2.x

[mojodna]

Primarily for compatibility with jest (used by npm test).

With node-0.12.7, jest does this:

$ npm test

> @panorama/[email protected] test /Users/seth/src/americanpanorama/panorama
> jest

/Users/seth/src/americanpanorama/panorama/node_modules/jest-cli/src/TestRunner.js:433
        const cacheA = testPerformanceCache && testPerformanceCache[a[0]];
        ^^^^^
SyntaxError: Use of const in strict mode.
    at exports.runInThisContext (vm.js:73:16)
    at Module._compile (module.js:443:25)
    at Object.Module._extensions..js (module.js:478:10)
    at Module.load (module.js:355:32)
    at Function.Module._load (module.js:310:12)
    at Module.require (module.js:365:17)
    at require (module.js:384:17)
    at Object.<anonymous> (/Users/seth/src/americanpanorama/panorama/node_modules/jest-cli/src/jest.js:13:18)
    at Module._compile (module.js:460:26)
    at Object.Module._extensions..js (module.js:478:10)
npm ERR! Test failed.  See above for more details.

[mojodna]

Why 4.2? It's an LTS release and we don't need functionality introduced since then.