Javadoc the new API

src/main/java/WayofTime/bloodmagic/api/IBloodMagicPlugin.java

@@ -1,6 +1,15 @@
 package WayofTime.bloodmagic.api;
 
+/**
+ * The main class to implement to create a Blood Magic plugin. Everything communicated between a mod and Blood Magic is through this class.
+ * IBloodMagicPlugins must have the {@link BloodMagicPlugin} annotation to get loaded by Blood Magic.
+ */
 public interface IBloodMagicPlugin {
 
+    /**
+     * Register mod content with the API
+     *
+     * @param api The active instance of the {@link IBloodMagicAPI}
+     */
     void register(IBloodMagicAPI api);
 }