Automatically Register/Reload Component Managers and Systems

[randomPoison]

Right now game code has to manually register all component managers and systems at startup, and has to manually reload them when the DLL is reloaded (if hotloading is enabled). This code is super boilerplate and we should be able to automate it to some extent. The easiest thing to do would be to create a macro that generates the init and and reload glue given a list of managers and systems, but I think we can do one better. I'd like to see if it's possible to create a compiler plugin to automatically generate the glue code without any need for the end use to do any work.

Minimum Feature Set

• [ ] Automatically generate the glue code for registering managers and systems.
• [ ] Allow for managers or systems to be in some way marked as not automatically added.
• [ ] Provide some means to manually register managers and systems.
• [ ] Provide some means to enable and disable the feature as a whole (it should probably be on by default, though).

  Extra Features to Explore

• [ ] Attribute (or something) to mark the priority for systems to ensure a specific ordering can be attained.

  Notes

• I think we'll have to require that all managers and systems that are auto-registered are Default otherwise we won't have any way of instantiating the objects.
• Better than specifying a priority for each system it would be double-extra cool if we could specify a list of dependencies that need to be run first and then automatically generate a processing order. Not only would this allow for more correct code, it would open up possibilities for parallelizing game code.

[randomPoison]

This task is large enough to be a major milestone of its own. The hotloading system is currently broken anyway so this will likely get started as part of a future overhaul to hotloading.

[randomPoison]

The ECS is going away (or at least getting majorly reworked) so this issue is no longer relevant.