CDK-260: Fix PartitionExpression for DateFormatPartitioner.

This moves the toExpression(FieldPartitioner) method into the
PartitionFunctions class. This allows accessor methods to be
package-private and puts the expression logic for both directions in one
place to avoid oversight.
DK-260: Revert change to TestMetadataProviders.
- use windows path conventions on windows
- don't assume Java default locale for date conversions
add cache hit/miss metrics to userAgent morphline command
disable date related test because *.xlsx solr cell parser is locale sensitive; other solr cell parsers appear not to be locale sensitive, after all.
organize imports
CDK-262: Tika parsers used by solrCell morphline command should not depend on the default Java locale
CDK-263: Upgrade cdk-morphlines-json module from jackson-databind-2.2.1 to jackson-databind-2.3.0
fix typo
CDK-263: Upgrade tika-morphlines-json module from jackson-databind-2.2.1 to jackson-databind-2.3.1
CDK-263: Upgrade tika-morphlines-json module from jackson-databind-2.2.1 to jackson-databind-2.3.1
CDK-266: Use random UUIDs for unique file names.
CDK-267: Add morphline command that parses an Avro Parquet file
CDK-267: Add morphline command that parses an Avro Parquet file
allow passing explicit Path objects to readAvroParquetFile command
Updated to fix broken link to documentation
Merge pull request #5 from tomwheeler/patch-1

Thanks!
CDK-269: Remove inaccurate log4j warning message.
CDK-269: Add warning about schema literal vs URI.
CDK-271: Add "addEmptyStrings" parameter to readCSV morphline command to indicate whether or not to add zero length strings to the output field.