Print to console

Is it possible to print to console while tests are running? I tried `Console.WriteLine` and `Debug.Log`, and neither of them work. The console just displays `# Testing in playmode #` header, then nothing until the tests are complete. `Debug.Log` does at least go to the log file, but not the console, and it's too slow.

Start by running the playmode tests described in the issue and compare Console.WriteLine and Debug.Log output during execution with the log file. Trace the test runner's console-output handling to determine where output is buffered; done means diagnostic messages appear in the console while tests are still running without waiting for completion.

Written by the indexing model from the issue text.