Simplify node system

OK, here's a simplified breakdown of what we do when we use a node module. The package.json points to node-main.js which handles all of the requiring, globals and load order, then returns the RemoteStorage object. 

I don't know why we had all that hocus-pocus before with the -node build, there's no reason we even needed a build, the point of a node require is that you can use the source directly, and also require dependencies without having to make a single file build.
looks like this variable is not available when including remotestorage.js in a web app - at least with Firefox; see #791