(- fix) s/world/unit/
(- new debug) Attempt to show depth into partial Execution
(- lib API fix) Cloning Aliens now copies instance-data
(new lib API) Add most primitives, and supporting API

Nukespace API expanded a bit to support the primitves implementation. Put some effort into ensuring that the JavaScript and Paws-side APIs mapped closely to one another, while still feeling natural in their own language.
(- meta refactor inc) Begin using Cakefile again; refactor Cakefile

Although I generally much-prefer using a set of scripts with `npm run-script`, that's become basically impossible to make Windows-friendly. Thus, I'm going to move all the project-meta-shit back into a `Cakefile`, for simplicity of cross-platform builds. Oh well.

In this commit, to get that started, I refactor things to:

 - avoid `spawn` and friends, to make Windows support easier
 - centralize project configuration in package.json
(- meta fix) Port the `clean` task