by JamesAn: Added CHANGELOG.txt

by JamesAn: Expanded scaffolding with UI for the module selection task.
  Adds automatic module detection in module selection task.
  Adds links to project pages for modules not installed.
  Uses External Links in module selection task to handle project page links.
  Adds an empty second install task.
  Abstracts scaffolding to generate code to connect each install task to its
    corresponding Form API definition and submission handler.
  Abstracts components of the DSNF in module selection screen so a list of
    candidate modules is translated into a set of radio buttons filtered
    through the module detector.