Service builder - Review edits

Hi Jesse,
This PR contains my full review and edits of the Service Builder chapter. It includes recent review/edits of custom SQL, model hints, service.properties, and core services section.

With respect to custom SQL, I made changes to explain each step in a general sense before demonstrating it with the Event Listing portlet. I also paired down the overview steps into 3 fundamental steps. I thought this simplified things up front. Each step is detailed with the content you provided.

Event listing portlet
- Fixed event date (was not being set properly for entity)
- Added use of model hints
- updated .jar files
- rebuilt service and wsdds

Replaced sdk github references with SDK .zip file download references. This goes with our plan (at least temporarily) to provide the SDK as a .zip.

Added transitions
- intro to model hints
- summaries of sections and chapter summary
- transitions to next sections

Wordsmithed

Please review. If you just have minor changes, please send onto Rich and copy me. I'm happy to go over any review items with you as I know this is a large review, being of the whole chapter.

Thanks!