[Package] Implementation of Tizen Package API

This branch includes a fully functional implementation of Tizen Package API. 

API specification can be found at:
https://developer.tizen.org/dev-guide/2.2.0/org.tizen.web.device.apireference/tizen/package.html

BUG=XWALK-443
I can't move it directly, since it will complain about the pkg_info undeclared. Anycase, I will change the logic a bit.