Assorted trivia in search.cpp

The only interesting change is the moving of
stack[MAX_PLY+4] back to its original position
in id_loop (now renamed Thread::search).

No functional change.

src/uci.cpp

@@ -182,7 +182,7 @@ void UCI::loop(int argc, char* argv[]) {
 
       else if (token == "ucinewgame")
       {
-          Search::reset();
+          Search::clear();
           Time.availableNodes = 0;
       }
       else if (token == "isready")    sync_cout << "readyok" << sync_endl;