Browser support

I did some file renames (to make it easier to add Bower support in the future) and added a wrapper in `safe-access.js` s.t. it can be used in Node.js or in the browser (direct or via AMD).

FYI, this [this article](http://ifandelse.com/its-not-hard-making-your-library-support-amd-and-commonjs/) why/how supporting multiple environments is a good idea.