Move ShimContext to its own file
Move AlterTableHelper into BasicDDLFunctions
Bundle bits of ALTER state into a struct
Pull ColumnName into public class
Allow group index specification to writeRow. Add overload.
Track drop, meta and data changes for group indexes during alter
Consolidate defintion change
merge nathanlws: Cleanup, and fix, group index handling during ALTER

Merge pull request #1020 from nathanlws/sql-layer/streamline-alter-gi-handling
https://github.com/FoundationDB/sql-layer/pull/1020
Update copy constructors to be consistent, even when nothing needs to be copied in that class.
Track a version number for the generated group.
Persist generated storage format descriptors.
Add conversion for data as well as meta-data.
Add format for Protobuf in Persistit.
Add unit test and IT tests.
Update copy constructor.
Use newer git-commit-id maven plugin
merge nathanlws: Use new git-commit-id Maven plugin

Merge pull request #1022 from nathanlws/sql-layer/newer-git-commit-id
https://github.com/FoundationDB/sql-layer/pull/1022
Per review comments, save generated format directly in Storage, rather than separately where it can get out of sync.
Do encode DATE and DATETIME as strings.
Revert file that didn't need to change at all.
Update test results for datetime fields.
Simple class for shimming an OutputStream to slf4j
Redirect stdout and stderr to slf4j