Added a Starfall Helper

Added new doclet file for generating a json file
Added a json.lua file for ease of generating
Added a SFHelper button in the editor
Added sfhelper.lua file
Changed sflib.lua to include sfhelper.lua

If you want to generate the doc.json file change the doclet type in the build_docs.lua file to doclet_json and it will build the docs. Upload the doc.json file to the official documentation website and change the address near the top of the sfhelper.lua file. I will keep a version hosted for a while until this may get accepted.
You will also need to update the doc.json file whenever you update the documentation on the website.