Pin master to -SNAPSHOT and -dev versions.

Ensure that we don't inadvertendly publish artifacts that aren't
final tagged versions. A future review will introduce tooling to
automatically and atomically increment these version numbers.

Testing Done:
% ./gradlew publishToMavenLocal
% ./pants setup_py src/main/python/twitter/aurora/config:config-packaged

Bugs closed: AURORA-10

Reviewed at https://reviews.apache.org/r/16228/