ECDR-40: Updated to use DDF registry.
Rename SImpleDynamicServiceIdentifier.java to SimpleDynamicServiceIdentifier.java

ECDR-40: Fixing incorrect filename.
Merge pull request #11 from mrmateo/ecdr40

ECDR-40: Updated to use DDF registry.
ECDR-XX: Fixing a spelling error and correcting variable naming.
ECDR-23: Updated source to properly support RANGE headers when resuming retrievals.
Merge pull request #13 from mrmateo/ecdr23

ECDR-23: Updated source to properly support RANGE headers when resuming retrievals.
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