move default salt to EMF obfuscator builder
diff --git a/plugins/org.eclipse.viatra.modelobfuscator.runtime.uml/src/org/eclipse/viatra/modelobfuscator/emf/uml/UMLObfuscatorBuilder.xtend b/plugins/org.eclipse.viatra.modelobfuscator.runtime.uml/src/org/eclipse/viatra/modelobfuscator/emf/uml/UMLObfuscatorBuilder.xtend
index f779f6b..db248e3 100644
--- a/plugins/org.eclipse.viatra.modelobfuscator.runtime.uml/src/org/eclipse/viatra/modelobfuscator/emf/uml/UMLObfuscatorBuilder.xtend
+++ b/plugins/org.eclipse.viatra.modelobfuscator.runtime.uml/src/org/eclipse/viatra/modelobfuscator/emf/uml/UMLObfuscatorBuilder.xtend
@@ -11,7 +11,6 @@
 package org.eclipse.viatra.modelobfuscator.emf.uml
 
 import org.eclipse.viatra.modelobfuscator.emf.simple.EMFModelObfuscatorBuilder
-import org.eclipse.viatra.modelobfuscator.util.ObfuscatorUtil
 
 class UMLObfuscatorBuilder extends EMFModelObfuscatorBuilder {
 
@@ -20,8 +19,6 @@
      */
     protected new() {
         super()
-        super.salt = ObfuscatorUtil.generateBase36RandomString(4)
-        super.prefix = "oC"
     }
 
     /**
diff --git a/plugins/org.eclipse.viatra.modelobfuscator.runtime/src/org/eclipse/viatra/modelobfuscator/emf/simple/EMFModelObfuscatorBuilder.xtend b/plugins/org.eclipse.viatra.modelobfuscator.runtime/src/org/eclipse/viatra/modelobfuscator/emf/simple/EMFModelObfuscatorBuilder.xtend
index 6d55361..d4967d0 100644
--- a/plugins/org.eclipse.viatra.modelobfuscator.runtime/src/org/eclipse/viatra/modelobfuscator/emf/simple/EMFModelObfuscatorBuilder.xtend
+++ b/plugins/org.eclipse.viatra.modelobfuscator.runtime/src/org/eclipse/viatra/modelobfuscator/emf/simple/EMFModelObfuscatorBuilder.xtend
@@ -26,7 +26,7 @@
  * the {@link StringObfuscator}, thus supporting reproducibility and restoration.
  * 
  * <p/>The default value of the seed is a random, 32 character long, base36 string created by
- * {@link ObfuscatorUtil#generateBase36RandomString}. The default value of the salt is empty.
+ * {@link ObfuscatorUtil#generateBase36RandomString}. The default value of the salt is a random, 4 character long, base36 string.
  * 
  * @author Abel Hegedus
  * 
@@ -35,7 +35,7 @@
 
     private ResourceSet inputRS
     private ResourceFilter filter
-    private String saltString = ""
+    private String saltString = ObfuscatorUtil.generateBase36RandomString(4)
     private BigInteger seedNumber = new BigInteger(ObfuscatorUtil.generateBase36RandomString(32), 36)
     private String prefix = "oC"
     private Map<String, String> obfuscationMap = null