Move ibc algorithm tests to tests/

The improved algorithm for calculating the inbreeding coefficient comes with a few nice tests. They were however part of the normal source code, which meant they would be packed into the final HTML as dead code.

This MR ports them over to our dedicated testing framework where they are loaded from an external file on demand. This means they don't get packed into the final HTML file.

To run tests, use App.Loader.executeTests() in the browser console.