Portland-based Urban Airship, the developer of mobile messaging and notification software, said today that it has acquired Tello, a developer of Apple Passbook management services. Financial term sof the buy were not disclosed. Tello was based in Palo Alto, California. Urban Airship said that Tello will remain in Palo Alto, and continue to offer up its products. Tello was venture backed by Bullpen Capital, SV Angel, and True Ventures.