Optimize partition pruning for Hive client

- replace usage of Warehouse.makeSpecFromName with a more efficient implementation
- build filters based on all partition keys, even if they are missing and call
  getPartitionNamesByParts. Use empty string as placeholder for missing filters
- short-circuit parsing partition key values and creating partition objects if
  we can determine the partition doesn't match the predicate
Add 0.85 release notes
[maven-release-plugin] prepare release 0.85
[maven-release-plugin] prepare for next development iteration
Fix tracking of input rows/bytes for JOIN stages

This is a little hacky, since we should really be tracking
just the inputs due to the TableScan operator for any given
stage. However, the current stats rollup system doesn't
support this.
Batch partition loading from the metastore