Sponge support

api/src/main/java/me/lucko/luckperms/api/Logger.java

@@ -0,0 +1,9 @@
+package me.lucko.luckperms.api;
+
+public interface Logger {
+
+    void info(String s);
+    void warn(String s);
+    void severe(String s);
+
+}

api/src/main/java/me/lucko/luckperms/api/LuckPermsApi.java

@@ -9,6 +9,7 @@ public interface LuckPermsApi {
     String getVersion();
 
     Datastore getDatastore();
+    Logger getLogger();
 
     User getUser(UUID uuid);
     User getUser(String name);