Merge pull request openzipkin#909 from openzipkin/http-tags

Adds constants for common binary annotation keys to http

[RELEASE] - new version: '1.30.2-SNAPSHOT'.

Merge pull request openzipkin#904 from openzipkin/revert-kafka-0.9

Reverts Kafka client to 0.8.x to avoid broker compatibility issues

Merge pull request openzipkin#900 from openzipkin/test

Ensures empty string isn't returned by getAllServiceNames

Merge pull request openzipkin#891 from openzipkin/no-httpvar

Removes httpvar config for collector sample rate

Merge pull request openzipkin#890 from openzipkin/reduce-customness

Reduces customness of zipkin-web by eliminating filesystem args

Doc bug

Merge pull request openzipkin#884 from openzipkin/version-bumps

Bumps versions, most notably Kafka to 0.9 and Finagle to 6.31

Merge pull request openzipkin#879 from openzipkin/test-time

Adjusts SpanStoreSpec to use realistic timestamps

Merge pull request openzipkin#873 from openzipkin/gradle-2.9

Updates to latest gradle 2.9