[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=XWALK-1617
Merge pull request #1885 from xinliux/xinliux/android/xwalk-sample

[Android] Add the sample code for demonstrating Embedding API