Remove container default

Just an opinion based on my personal learning experience with this library.

I’d like to suggest removing the default value for container in the patch function.

I found it quite surprising that there was any default at all - but since the default is document.body, your first experience, if you’re following the example, will be that of your own document getting wiped out, which was pretty surprising to me.

Also, when looking at the example in the README for the first time, my first thought was, “if both of the arguments are virtual DOM nodes, how does it figure out which real DOM element to updated?”

Of course, you learn these things quickly if you start poking through the source-code, but most people will likely jump in without reading documentation, or copy/pasting the example - making this argument non-optional might remove any confusion about how a target element is established and/or what happened to your existing body-content.

Defaults don’t always curb the learning curve - sometimes they increase it.

[jorgebucaran]

No, I like your changes and just merged them. #41

[mindplay-dk]

Let’s leave the PR open then, I’ll do both of these before the merge, yeah?