Fix for missing dependency 'ms'.

This should fix the error from a missing dependecy 'ms'.

/var/projects/node_modules/serve-favicon/index.js:16
    `var ms = require('ms');`


---

    Mean app started on port 3000 (development)
    /var/projects/test/node_modules/meanio/node_modules/q/q.js:126
                    throw e;
                          ^
    Error: Cannot find module 'ms'
    at Function.Module._resolveFilename (module.js:331:15)
    at Function.Module._load (module.js:273:25)
    at Module.require (module.js:357:17)
    at require (module.js:373:17)
    at Object.<anonymous> (/var/projects/test/node_modules/serve-favicon/index.js:16:10)
    at Module._compile (module.js:449:26)
    at Object.Module._extensions..js (module.js:467:10)
    at Module.load (module.js:349:32)
    at Function.Module._load (module.js:305:12)
    at Module.require (module.js:357:17)
    at require (module.js:373:17)
    at Object.<anonymous> (/var/projects/test/packages/system/app.js:7:13)