SpongeFabric Progess

[LogicFan]

The SpongeFabric is still in a very early stage, there will be many things that need to be finished before it can runs. Here is a tracker of what is still needed,

1. Add a proper entry point in the fabric loader to allow download dependency and load sponge plugins ([Discussion] A super-early-entry-point (or loader-plugin) FabricMC/fabric-loader#486).
2. Waiting for fabric release mixin 0.8.4 for their fabric loader (Update for new mixin FabricMC/fabric-loader#468).
3. Write PluginEngine for SpongeFabric that cooperates with the fabric loader (Blocked by 1).
4. Modify the mixin classes to cooperate with the fabric API. (Block by 3)
5. Waiting for SpongeVanilla to be stable.