Kill no longer necessary PACKAGE_ID

:skull: death to old cruft.
As no active package uses the package_id anymore, remove it completely.

While here also remove dead addTangoAttribution() method nothing calls anymore.

This should require a minor version bump as it breaks the api.
Bump the package minor version as dropping the PACKAGE_ID constant and use breaks the public API.
Merge pull request #21 from isaacgrant/kill-package-id

Kill no longer necessary PACKAGE_ID