Merge pull request #244 from ekolesnikov/constructor-update

Added extra constructors to selectively prevent ExpressionManager from instantiating ExpressionFactoryImpl 

modules/activiti-engine/src/main/java/org/activiti/engine/impl/el/ExpressionManager.java

@@ -60,7 +60,15 @@ public class ExpressionManager {
 	    this(null);
   }
   
+  public ExpressionManager(boolean initFactory) {
+	    this(null, false);
+  }
+  
   public ExpressionManager(Map<Object, Object> beans) {
+	  this(beans, true);
+  }
+  
+  public ExpressionManager(Map<Object, Object> beans, boolean initFactory) {
 	    // Use the ExpressionFactoryImpl in activiti build in version of juel, with parametrised method expressions enabled
 	    expressionFactory = new ExpressionFactoryImpl();
 	    this.beans = beans;