Finalized some fields, removed redundant code, various other fixes

src/main/java/fr/xephi/authme/command/CommandManager.java

@@ -20,7 +20,7 @@ public class CommandManager {
     /**
      * The list of commandDescriptions.
      */
-    private List<CommandDescription> commandDescriptions = new ArrayList<>();
+    private final List<CommandDescription> commandDescriptions = new ArrayList<>();
 
     /**
      * Constructor.

src/main/java/fr/xephi/authme/command/CommandParts.java

@@ -12,7 +12,7 @@ public class CommandParts {
     /**
      * The list of parts for this command.
      */
-    private List<String> parts = new ArrayList<>();
+    private final List<String> parts = new ArrayList<>();
 
     /**
      * Constructor.

src/main/java/fr/xephi/authme/command/FoundCommandResult.java

@@ -13,15 +13,15 @@ public class FoundCommandResult {
     /**
      * The command reference.
      */
-    private CommandParts commandReference;
+    private final CommandParts commandReference;
     /**
      * The command arguments.
      */
-    private CommandParts commandArguments;
+    private final CommandParts commandArguments;
     /**
      * The original search query reference.
      */
-    private CommandParts queryReference;
+    private final CommandParts queryReference;
 
     /**
      * Constructor.

src/main/java/fr/xephi/authme/command/executable/converter/ConverterCommand.java

@@ -90,7 +90,7 @@ public class ConverterCommand extends ExecutableCommand {
         vauth("vauth"),
         sqltoflat("sqltoflat");
 
-        String name;
+        final String name;
 
         /**
          * Constructor for ConvertType.