Added EnableTranspositionTable UCI option to enable/disable transposition table.

src/tt.h

@@ -84,6 +84,10 @@ public:
     return &table[mul_hi64(key, clusterCount)].entry[0];
   }
 
+#ifdef EVAL_LEARN
+  static bool enable_transposition_table;
+#endif
+
 private:
   friend struct TTEntry;