Add mixin extras

src/main/java/moe/nea/firmament/init/MixinPlugin.java

@@ -18,6 +18,7 @@
 
 package moe.nea.firmament.init;
 
+import com.llamalad7.mixinextras.MixinExtrasBootstrap;
 import org.objectweb.asm.tree.ClassNode;
 import org.spongepowered.asm.mixin.extensibility.IMixinConfigPlugin;
 import org.spongepowered.asm.mixin.extensibility.IMixinInfo;
@@ -29,6 +30,7 @@ public class MixinPlugin implements IMixinConfigPlugin {
 
     @Override
     public void onLoad(String mixinPackage) {
+        MixinExtrasBootstrap.init();
     }
 
     @Override

src/main/java/moe/nea/firmament/mixins/MixinDrawContext.java

@@ -1,2 +0,0 @@
-package moe.nea.firmament.mixins;public class MixinDrawContext {
-}

src/main/kotlin/moe/nea/firmament/events/FirmamentEvent.kt

@@ -24,8 +24,8 @@ package moe.nea.firmament.events
  * Typically, that event bus is implemented as a companion object
  *
  * ```
- * class SomeEvent : NEUEvent() {
- *     companion object : NEUEventBus<SomeEvent>()
+ * class SomeEvent : FirmamentEvent() {
+ *     companion object : FirmamentEventBus<SomeEvent>()
  * }
  * ```
  */