Support for dependency management (other than the "window" global)

I'm using routie on a project that uses dependency management, with [Browserify](https://github.com/substack/node-browserify).

Up until now, I used it as a global (`window.routie`) but it would be better if it could be required by the modules that need it.

The pull request adds support for `require` (ex: Node.js) and `define` (ex. RequireJS). When included in the browser (`<script src="..." />`), it still adds itself to the window global.

The `noConflict` method should still work.