GitHub restructure and misc minor fixes:
- agentsets.own: input now is mixed names and name/default pairs
- Cakefile: try to help with maps, still wonky in CoffeeScript
- Convert to Math.atan2.  Doh!
- template.html -> models/
- New layout: .gitignore: ignore all toplevel .js, .map, .coffee files
- Lib: add .map; remove .coffee
- Tools: coffee-script.js
- New file layout:
    Cakefile    cake file for build, docs etc.
    LICENSE     GPLv3 License
    README.md   This file
    docs/       Docco documentation
    extras/     AgentScript extensions
    lib/        All .js/min.js and .map files
    models/     Sample models
    src/        Component .coffee files for agentscript.coffee
    tools/      coffee-script.js and others