Change base class for JSON objects from `Object` to `AcediaObject`.
Rename some classes/functions/structures/variables to
be more compact and/or better convey their meaning.
Add appropriate API that contains constructors for JSON objects.
We want all actors and objects defined in Acedia to share
a global namespace that provides an access to important variables
(such as `Acedia` reference) and functions.
We add a `Global` singleton and `AcediaActor` / `AcediaObject`
base classes with a quick accessor to it's instance (`_` / `_()`).
