cartographer

Author	SHA1	Message	Date
Christoph Schütte	f6a7dfd07b	Update Travis Docker file for Trusty to build gRPC code (#709 ) [RFC=0002](https://github.com/googlecartographer/rfcs/blob/master/text/0002-cloud-based-mapping-1.md)	2017-11-24 22:08:51 +01:00