We need to build a simple android demo that embeds the web map

[dadiorchen]

We already build a dedicated version of web map for this goal: https://alpha-dev.treetracker.org/ (Web Map Client version 2.6.0-demo.1) this task is about creating a simple android app to test these things:

1. Embed the web map client (https://alpha-dev.treetracker.org/) by web viewer in this android app.
2. When zooming in on the map, and clicking the single tree icon on the map, the wrapper app (Android app) can receive the event that brings the tree object, by listening to the event of the map, the wrapper app is able to develop some custom feature based on our map.

The significance of this demo is that we will give this app as an example to our partner organization/company that has its own mobile app and want to integrate our treetracker map.

An imagine effect of this app:

[dadiorchen]

As shown here, in the web map client, we trying to use postMessage to do the communication:

        if (window.parent) {
          log.warn('DEMO:ok message parent');
          window.parent.postMessage('DEMOxxx foo', '*');
        }