Multiple url support, CLI parsing module and dynamic build

Pretty massive update.

I hope you like the build of `penthouse.js`. It retreives the values from `package.json` so that they are always in sync. No more manually updating the preamble :-) 

The CLI parsing is now done by a separate module. 

And there is also support for multiple urls. If you just pass one then it functions the same as before. But the order of the css and url had to change, so that is a breaking change.

fixes #10
Actually it is correct. The usage info is meant for end-users. That functionality is still there and works exactly as it says.

The additional functionality is only known to us, and so we do not have to expose it. It is exposed through the node module, though, and that bit needs a bit of work before it can be used by end-users. See issue #15 

But I thought we might do that later, since everyone will be using the node module through the npm registry, and the documentation is still correct for that.