better organization

hi. i like your idea. i plan to use it on node.js. i noticed you started a node.js-like module. however it was pretty confusing reading your committed sql.js vs. the one hosted on your demo which was minified. i don't think they are exactly the same.

anyway i moved things around into a folder structure i think is more conventional. i also added a mocha test.coffee you can run with `npm test` to verify things are working.

i also was able to get it reading and writing the `.sqlite` binary data format to/from disk with node.js' `fs.writeFile()`.

it would be cool if you could update and move your module code out of sql.js and into the coffee/node-sqlite-purejs.coffee file. i recommend we keep following the asynchronous callback pattern which is conventional to node.

also if the node-sqlite-purejs.js file (which compiles from the coffee one) could be loaded in the browser and work just as well as in node, that would be sweet. i see you were trying to achieve that with your module but i don't think you got the node part quite down, or maybe just not for the latest version of node.

anyway thought i would share alike. best wishes!