doc and javadoc
cleanup
Fix compilation warnings and redundant imports.

Also make sure -Werror is enforced since it was not taking effect
properly due to multiple "compilerArgument" parameters. The correct
way is to use "compilerArgs" which takes a list of "args".
Enforce no warnings in cdk-maven-plugin and cdk-tools.
Add missing @since tags.
Remove dependency on Commons Configuration. This dependency was being
indirectly fulfilled by Hadoop, but it would be better not to introduce
a new explicit dependency in CDK for such a small piece of code.
CDK-168. Error when trying to delete a dataset.

The code was trying to delete the data directory non-recursively, even
though it may not be empty. This doesn't seem right: the data directory
should be managed by the FileSystemDatasetRepository.
CDK-169. mvn cdk:create-dataset fails for hcatalog datasets
bit more doc
CDK-173: Exclude unnecessary hadoop dependencies from cdk-morphlines-solr-core
bit more doc
also report fileDescriptorCountRatio metric
add another test to load Index Schema
add more test coverage
more doc
use relative doc links
make metric filters immutable to prevent potential visibility races
make units parametrizable
bit more doc
bit more doc