Update to new ColumnMetadata api
Change column comment to be empty string instead of null
Configurable Hive SerDe, InputFormat, OutputFormat in CreateTableAsSelect

Closes #1453
added number of runs and fixed time zone header
Factor a TestingPrestoClient out, add a single node server query runner.

This removes the query specific code from the DistributedQueryRunner
and adds a new QueryRunner that uses a real, albeit single-node,
embeded discovery TestingPrestoServer. Unlike the LocalQueryRunner
which fakes a presto engine, this is a full-fledged server.