Add classloader to engine from PrologMachineCopy

src/lang/Prolog.java

diff --git a/src/lang/Prolog.java b/src/lang/Prolog.java
index 204cf88..48cdf76 100644
--- a/src/lang/Prolog.java
+++ b/src/lang/Prolog.java
@@ -176,6 +176,7 @@
       trail = new Trail();
       stack = new ChoicePointStack(trail);
       copyHash = new IdentityHashMap<VariableTerm, VariableTerm>();
+      pcl = pmc.pcl;
 
       // During restore there is no need to copy terms. clause/2 inside of
       // builtins.pl copies the predicate when it reads from internalDB.