Update grpc, protobuf, datastore and gax dependencies, regenerate SPI classes (#1273)
Update grpc, protobuf, datastore and gax dependencies, regenerate SPI classes (#1273)

* Regenerating SPI classes
* Updating grpc to 1.0.1 and protobuf to 3.0.0
* Converting PageAccessor to PagedListResponse
* Adding auto-generated tests for logging
* Removing some unused imports
* Updating datastore proto dependency
* Removing unnecessary auto-value dependency
* Using correct version of netty-tcnative-boringssl-static
googleapis/java-core,googleapis/java-core,googleapis/java-core