stewardess is now browserifyable

make `require('mongoose')` and expression so browserify will skip it.

Allow for setImmediate, process.nextTick, or fall back to setTimeout.

![7htcfhq](https://f.cloud.github.com/assets/678338/1010457/2aca2bc2-0b4b-11e3-913a-9faf1c58eb80.gif)