Intuitive approach running examples

[doodlewind]

For now examples are built by npm scripts, which was a workaround for build test. Now that Ava is integreted, this is no longer necessary. So we need new way running examples. Requirements:

• Running examples does not couple with main package.json.
• Example can have more side effect like HTML view and network request, with its standalone package.json or simply run in node.
• All examples should have similiar way of running, with a unified README in examples folder.

[doodlewind]

Done! npm run example -- args works great for this.