0.4.0

We have now tested version 0.4.0 on our big project and it seems to work fine. So, letting go of beta prefix now.
Though, some bugs could appear, of course.

Fixed

• $logger removed from vm scope to prevent overlapping with possible public method

New

• Now possible to use v-on: directive on components to user cross-VM comunication. Could be removed in future because it can get in the way of client-only features
• Thanks to the issue added new example (examples/server-express) on express.js
• vue-server got slightly faster :)