Feedback & Fixes from last training course

I am capturing this as a Jira bug so it is not lost ...

USER VISIBLE PROBLEM

• the update site is needed before we release; or we need to remove that section from the walkthrough

FRAMEWORK PROBLEMS

• hard to debug when IResolveAdapter does not have target provided NPE everywhere; we need some try/catch checks
• IGeoResource superclass was not resolving to an IGeoResource as expected by CatalogUI.title method; all the UDIG IGeoResource implementations perform this
  function so we never noticed the mistake
• there is no way to clear a single entry from the StyleBlackboard (you can clear the whole thing; but not a single entry)

API PROBLEMS

• refractions SelectionListener vs eclipse SelectionListener; no reason for confusion we should rename ours (it does not appear to be referenced anywhere in
  the code base)
• Renderer is in an internal class; making everyone unhappy implementing it
• When choosing between CSVRenderer and ColorCSVRenderer we have a problem; when there is no color both render metrics evaulate to 0 entries of the style blackboard. They are tied. The ColorCSVRenderer actually wants a Color to be on the blackboard. We can perform this check by hand at the RenderMetricsFactory; but it would be nicer to fold in all style/how well can I draw questions into the single RenderMetricsClass. And leave RenderMetricsFactory to check the data....