ofxEntityX is a (very small) wrapper around EntityX, a commonly used library for Entity Component Systems (ECS).
For those of you not familiar with ECS, it's a different way of thinking; instead of using complex objects, one uses Entities. To build your entities you add Components to them, for example its position and speed in space. Systems are used to control and update all entities, for example, updating the position component using its speed component. When starting with ECS I found Cowboy Programming quite useful, as well as GameProgrammingPatterns and Bomberman Case Study
The addon already contains a built version of EntityX, as well as a simple example on how to use it. Its all work in progress currently, I will be adding more examples and readme soon.
The addon is fully functional in Windows, Visual Studio 2015.