Fixing MockDataGenerator to generate employee.jobId values that match generated jobs.

This is in preparation for adding tests for GROUP_BY queries.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=77784401
Disallowing not meaningful projection lists in SELECT queries.

Specifically:
- If GROUP_BY is specified: Any non-aggregated column that appears in
the projection list *must* also appear in the GROUP_BY list.
- If GROUP_BY is not specified: Aggregate and non-aggregated columns can't
be mixed (result does not make sense).

Also in this CL:
- Modifying performance test that was no longer valid (projection of mixed
columns)
- Deleting end-to-end test that is no longer valid.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=77821869
Implementing GROUP_BY in SELECT queries.

Specifically:
- Adding "groupByColumn" information in ProjectStep/ProjectNode,
and updating logic to perform grouping as needed.
- Modifying the way RelationTransformer handles the cases
where aggregated columns exist.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=77878511
Add doctype and meta charset for generated HTML in run_test_server.js.
Change line break from \n to \r\n for easier inspection on Windows.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=77952427
Adding hr_schema Department sample data.

This is in preparation of testing 3+ table joins, for
example between job, employee, and department tables.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=77966217
Modifying PushDownSelectionsPass to push down JoinPredicates too.

Currently only ValuePredicate nodes are being pushed down. This will
allow later passes to convert cross-products nodes to join nodes when
possible.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=77967760
Add missing parameter usage.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=77968329
lf.testing.hrSchemaSampleData shall not assume a global variable db.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=77973235
Correctly deference payload in order by step when the query involves join.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=77977247
Update movie DB demo to offer pure IndexedDB implementation for comparison
of the efforts and execution speed.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=77980659