Wow, this is fantastic work.
Jeroen Hoekx has added the ability to represent the host file in YAML
in addition to the existing INI file format. Ordinarily this would
just be a format change, but he's gone quite a bit beyond that, also
refactoring Inventory considerably (which is great). If you use this
format you can also define variables per groups of systems and also
variables for specific systems all in the inventory file.
Here is an example from the unit tests (again, this is OPTIONAL... the
INI file still works fine so no change is required if you don't want
to use this)