Re-add "Cache line aligned TT"

But this time do not play with pointers, in
particular do not assume that size_t is an
unsigned type of the same width as pointers.

This code should be fully portable.

No functional change.

src/tt.h

@@ -85,7 +85,7 @@ class TranspositionTable {
   static const unsigned ClusterSize = 4; // A cluster is 64 Bytes
 
 public:
- ~TranspositionTable() { delete [] table; }
+ ~TranspositionTable() { free(mem); }
   void new_search() { generation++; }
 
   TTEntry* probe(const Key key) const;
@@ -98,6 +98,7 @@ public:
 private:
   uint32_t hashMask;
   TTEntry* table;
+  void* mem;
   uint8_t generation; // Size must be not bigger then TTEntry::generation8
 };