Misc fixes.

Closes a few old youtrack issues which I don't remember because I had
like 30 tabs open, and a few other issues which I found while testing
some of those.

worldedit-core/src/main/java/com/sk89q/worldedit/internal/command/exception/WorldEditExceptionConverter.java

@@ -61,7 +61,7 @@ public class WorldEditExceptionConverter extends ExceptionConverterHelper {
     }
 
     private CommandException newCommandException(String message, Throwable cause) {
-        return new CommandException(TextComponent.of(message), cause, ImmutableList.of());
+        return new CommandException(TextComponent.of(String.valueOf(message)), cause, ImmutableList.of());
     }
 
     @ExceptionMatch