Support multi-threaded interpretation.

[unserializable]

To be relevant in modern system's programming, WSA + Whitelips need to offer support for multi-thread/multi-process execution models, to take advantage of multi-core processor architectures.

In the Whitelips IDE, multiple processes/threads and stacks should each get their own view.

Suggestion is to use preliminary codename 'Hotlips' when talking about the matters concerning multi-thread whitespace interpreter.