#180 - Simplication of render core system

[PowerfulBacon]

Currently it is way too complicated to do many things and we really just want to simplify things in general.

Firstly, render cores are a complicated mess. We should take an approach with a plane system similar to byond where:

• By default rendering to a plane will just draw the item with a default render core setting
• You can hook onto each plane by its integer value and add in custom rendering behaviours and special effects (change the plane shader etc.)
• You can tell the plane to not render at all and instead draw to a surface which can be used somewhere else.

[PowerfulBacon]

We will merge renderers and render cores into 1, remove the need to specify a default render core.
We also need to consider how to handle special filter effects applied to objects/renderers such as outlines or blurs. This will likely be rendering to a texture, before passing it through a simple renderer with a shader with the result going to the source texture.