[AppSkeleton] version should be passed in template data
[App] Add missing version properties to test data
os.tmpdir() was called os.tmpDir() in node 0.8...

This causes the tests to fail on node 0.8 (travis), which
wasn't happening before (and suggests the tests were incomplete).
Add a --version option to xwalk_apkgen
Fix functional tests by adding App.version numbers