[Android] Add support for setting version codes in apk

Add support for specifying android version codes, which is necessary
for publishing multiple apk to google play. Follows the recommendation
for ABI in
http://software.intel.com/en-us/blogs/2012/11/12/how-to-publish-your-apps-on-google-play-for-x86-based-android-devices-using

Added some tests to make_apk_test and published x86 and arm crosswalk
apk to google play.

Addressed review comments
Merge pull request #1423 from rscohn2/master

[Android] Add support for specifying android version codes