Major update to the Stanbol Enhancer Transformer Adapter

This fixes:
* Issue #1: Adds support for Enhancement Chains
* Issue #2: The Adapter now uses the Stanbol ContentItem Reader/Writer
* Issue #3: as STANBOL-1404 is now implemented

This changes:

* Added a ChianWrapper
* The EngineWarpper was removed as a Engine can be wrapped by using the SingleEngineChain and the ChainWrapper
* The paths for the transformer are no `transformer/engine/{engine-name}`, `transformer/chain/{chain-name}`
* extended the pom of the service module to require Java 1.7; Added Bundle Metadata; updated plugins; added the installBunlde profile
* minor updates to the Transformer.ftl