[Android] Refine the scripts for generating app packaging tool.

Currently there are lots of issues to generate app packaging tool:
1. Lots of unneeded class files are copied.
2. Two .dex.jar files are not needed by app packaging tool.
3. Some internal Java files like NativeLibraries are compiled when
packaging web apps. They should be handled internally inside of
xwalk runtime.
4. Refine the code for generating app packaging tool.
5. Invalid the python file mode.
6. Merge two jars for runtime activity and runtime client.
Fix all above issues with the changes for gyp generation and the
generation python tool.

BUG=https://crosswalk-project.org/jira/browse/XWALK-608
Merge pull request #1265 from yongsheng/refactorembedded

[Android] Refine the scripts for generating app packaging tool.
[Runtime] Implement onSuspend event support.

"onSuspend" event is sent to the main page before it is closed.
This gives the application an opportunity to do some clean up.

When application process manager finds that the last open window is closed,
it sends 'onSuspend' event to main page. The event handler is
executed first in main page, then a finish event is sent out.

The application process manager is an observer of finish
event so that it closes main page when notified.