Scratch activecode starter code

For languages like Java or C++, significant boilerplate code is needed to test out a chunk of code. This makes the Scratch activecode harder to use if I want to say test out a string function's behavior.

For books using those languages, it would be useful if there was already a main function (C++) or a class with a main function (Java) so that the reader could just focus on adding the code they want to test.

Issues / options:

1. The desired starter code might differ from book to book. Should the starter code be something that gets specified by a book author? Or at least a way to override whatever the default is?

2. An author might want to provide a few different "templates". In C++, I could see wanting one template that has a main function and another that sets up a simple unit test. This feature might also be useful in a language like Python - in a book that made heavy use of turtle graphics or media processing, the author might want to provide templates with the necessary setup code for those environments. Perhaps an author could describe environments with a title and some starter code and a drop-down would allow the user to pick a template.

No files, tests, or entry points are named in the issue. Start by locating the Scratch activecode implementation and how books currently configure activecode; clarify whether authors should provide one starter program or selectable templates for languages such as Java, C++, and Python. Done should include a decided configuration approach and working author- or book-specific starter templates.