Update to airbase 15
Allow optimization of subexpressions in certain cases
Only start testing server once per class
Fix information schema predicate extraction
Extract helper method for getTables test
Fix getTables test

The test should succeed now that it works on the server.
Configure logging for tests
Add missing dependency
Add JSON format for EXPLAIN
- Currently only Inputs (input tables) is included.
Add 0.60 release notes
Fix scheduling bug where drivers queued in TaskExecutor are not counted

Create DriverContext when split is added instead of waiting until a thread is associated with the split.
Upgrade to airlift 0.85 and discovery-server 1.17
Move commons-logging exclusion to root POM
Bundle tpch and cassandra plugins with server
Fix dependency scope for commons-math
Check for no tpch nodes when generating splits
Wrap release notes text
Improve TPCH no nodes error message
[maven-release-plugin] prepare release 0.60
[maven-release-plugin] prepare for next development iteration