spike: evaluation grammar for klipse output validation

As a teacher I would like a way to make sure my students don't simple write the expected output of the function. Example
> if the assigment asks to write a sums two numbers, the student could simply bypass the work and just write the expected output.

The issue names Klipse output validation but no repository files or tests. Start by locating the validation entry point and establish the grammar requirements and acceptance checks for rejecting hard-coded expected output; done means an agreed, documented design.

Written by the indexing model from the issue text.