[Android] Add version number tracking for packing tool.

The version number of packing tool is the same as that of XWalk.
With the version, it would be easier to track bugs for packing tool.
Usage: python make_apk.py -v

BUG=https://crosswalk-project.org/jira/browse/XWALK-163
Merge pull request #1087 from junmin-zhu/version

[Android] Add version number tracking for packing tool.