beacon documentation

To support the recent conversation about Beacon, we put together an updated documentation using Documenter.

To play with it:

1. Load GToolkit (this will also load Beacon)

2. Inspect

IceRepository repositoriesLocation / 'feenkcom'/ 'gtoolkit' / 'doc' / 'beacon' / 'index.pillar’. 

Enjoy,

The feenk team