mkdir should return true if already exists

Author: burdo

src/main/java/org/comroid/api/io/FileHandle.java

@@ -83,6 +83,7 @@ public boolean isDirectory() {
 
     @Override
     public boolean mkdirs() {
+        if (exists()) return true;
         if (isDirectory())
             return super.mkdirs();
         else return getParentFile().mkdirs();