Revert "Store moves sent with "position" UCI command"

This reverts commit 0d68b523a3.

After easy move semplification this machinery is not
needed anymore (because of we don't need to know if a
root move is a recapture)

No functional change.

src/search.cpp

@@ -44,7 +44,6 @@ namespace Search {
   Color RootColor;
   Time::point SearchTime;
   StateStackPtr SetupStates;
-  MovesVectPtr SetupMoves;
 }
 
 using std::string;