ECDR-42:
 - Refactored endpoint code to remove the duplication between the search and broker and to leverage an abstract class
 - Updated Atom Transformer to make a link to the metadata if there is no explicit product (so the metadata would be the product)
 - Added extra validation for some query parameters
ECDR-42: updated javadoc class description as it was originally copy-pasted from the CDR Source
ECDR-42: updated code to use the metadata action to view the metadata as the "product".  Previously it was hardocded to use the transform=metadata with the REST Endpoint.
Merge branch 'master' of https://github.com/di2e/ecdr
Merge pull request #14 from jvettraino/master

ECDR-42: CDR CTK Compliance