[Android] Add the sample code for demonstrating Embedding API

Add the sample code for demonstrate the usage of some Crosswalk Embedding API, covering ones:
1. XWalkView.getAPIVersion()
2. XWalkView.getXWalkVersion()
3. XWaklNavigationItem.getUrl()
4. XWaklNavigationItem.getOriginalUrl()
5. XWaklNavigationItem.getTitle()

BUG= https://crosswalk-project.org/jira/browse/XWALK-1617