Better mobx-vue develop experience

[nighca]

Perhaps we can offer better vue-mobx develop experience by hijack render method of vue component.

Then we can access observable value from MobX store directly in vue components' render method (or template).

It is somewhat like the way mobx-react does. It may not be suitable for vue, as vue provides its own observable mechanism and consume data in more ways (such as computed, watch, ...) other than render method.

But it is worth a try.