Preview 3

Contains incremental improvements towards the first stable release.

New features:

• Support columnar scan format
• Expose partitioning information through KuduPartitioner
• Add support for scanner keep-alive

Optimizations and refactors:

• Refactor sidecar handling and scan parsing
• Add type and null checks to RowResult.GetRawFixed()

Bug fixes:

• Make empty projection scans consistent between rowwise and columnar formats
• Fix improper use of pipelines during connection shutdown

Misc:

• Update dependencies
• Add more XML documentation comments

Testing:

• Port more tests from the Java client