Gpii 120 javihernandez

Hi!

I made these changes in order to finish the build, so I can use this branch to keep including changes for the main pull request.

At this moment, I've fixed the jtar dependency problem and added a check for the assets directory.
Additionally, I can see that "install_to_device.sh" is not pushing the activitymanager module to the phone (I will keep pushing changes).

Cheers,
Javi