WebView enhanced.

[zero-meta]

Related APIs:

• webView:registerCallback(name, function): Register a Lua function that can be called from JavaScript
• webView:on(eventName, listener): Listen for events from JavaScript
• webView:send(eventName, data): Send data to WebView
• webView:injectJS(script): Inject JavaScript code into WebView

See more detail in this forum topic and this repo.

[tomprice]

This looks very handy! @Shchvova Can this be merged?