ECS: allow multiple systems acting on the same set of components #5
Description
At the moment, an ECS system can be setup to run on all entities with a common set of components. This is done with the LinceECSAddSystem.
However, only one system can be setup per set of components. One could improve this by allowing multiple systems to act on the same entities. These systems would be stored in a stack that can be "pushed" or "popped" with e.g. LinceECSPushSystem and LinceECSPopSystem. This also allows layering of systems.