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CDK-214. Support specification of DatasetRepository by URI in Log4jAppender.
Maven plugin is missing hive-exec dependency.
CDK-216. Allow schema to be specified by classname in Maven plugin.
CDK-183	Schema creation and migration should validate that key fields of entity
schemas that belong to same table match

CDK-146	Validate that only one schema definition in a table has an occVersion
mapping

CDK-145	Enforce schemas that share a table don't clash in columns
The HBaseDatasetRepository now supports loading a dataset that is
a composite of multiple HBase datasets that share a table. Prior
to this, one had to create a dataset of the composite, but with
this change, creating a composite is now loaded at runtime (only
the sub entities need to be created).

The one downside to this is that the Dataset created now returns
a Map type instead of an entity that has member fields that make
up the composite type.
CDK-218. Support schema updates for Hive/HCatalog dataset repositories.
CDK-75. Write Parquet datasets from Crunch
Remove unneeded check for UnsupportedOperationException following CDK-218.
CDK-141: Fields that can be incremented with HBase's atomic increment or Accumulo's
aggregators need to have a special anntoation.

Added new mapping type called counter. Only int or long avro fields can be annotated
with this mapping type, and only fields annotated with this mapping type can be
incremented atomically.

Added a new set of schema validations for verifying the following:

1. An entity schema can't contain multiple occVersion mapping fields
2. An entity schema can't contain both an occVersion field and a counter
   field.
Fixing a bug in Key#reuseFor(entity).

Key#reuseFor(entity) checked if the entity was an IndexedRecord, but
then used the index in the partittion strategy rather than looking up
the correct field index. Since there is no mapping available, get(int)
shouldn't be used at all.
CDK-177: Adding range view tests.

This adds general tests under TestRangeViews and specific tests for the
FileSystemView in TestFileSystemView. The FileSystemView is not entirely
working: testCoveringPartitions needs to be implemented, and it
overrides testLimitedWriter because writers don't currently respect
views. These are overridden to avoid breaking the build.
CDK-177: Add new Key constructors.

Now that the Key.Builder has been removed, Key needed some convenience
constructors:
* new Key(PartitionStrategy, Object) for entities
* new Key(PartitionStrategy, Marker) for markers
CDK-177: Update TestRangeViews.

The "current" event is within some of the range tests. This bumps its
timestamp ahead a little.
CDK-177: Remove useless FS newAccessor.

This is implemented in AbstractDataset, the definition in
FileSystemDataset was not needed.
CDK-177: Update FS writers for Views.

This commit updates the FS writers to stop using the Dataset partition
functions in favor of views. The major change is that there is no longer
a hierarchy of PartitionedDatasetWriters, but one per View (if
partitioned).

Before this, PartitionedDatasetWriter would use the partition dataset to
instantiate inner writer. Now, the backing View does not change and it
instantiates file writers directly rather than relying on the inner
Dataset to not be partitioned (at some level) and finally creating the
file writers. A consequence is that data file writers need to be
instantiated by both the View (if not partitioned) and by the
PartitionedDatasetWriter (otherwise). This commit introduces
FileSystemWriters#newFileWriter to instantiate file-based writers for
both.

One last change: the deprecated constructor for PartitionedDatasetWriter
is has been removed rather than updated before being removed later.

This also re-enables the testLimitedWriter test, which is now passing.