OPTIMIZATION: 50% speedup of `hdtSearch'.

Changed the end-of-line and flush command `std::endl' to emitting a
regular newline character.  This results in a 52% speedup, measured
over the 10M triple SP²B dataset, according to the following command:

    ./hdtSearch -q "? ? ?" 10M.hdt > out.nt

The detailed statistics are as follows (measured 5 times before and
five times after this commit; the unit is seconds):

  - Old: 23.375 23.027 23.216 23.630 23.368 (avg. 23.32sec)
  - New: 10.876 11.227 11.077 11.110 11.072 (avg. 11.07sec)

Author: wouterbeek

libhdt/tools/hdtSearch.cpp

@@ -115,7 +115,7 @@ void iterate(HDT *hdt, char *query, ostream &out, bool measure, uint32_t offset)
 		while(it->hasNext() && interruptSignal==0) {
 			TripleString *ts = it->next();
 			if(!measure)
-				out << *ts << endl;
+				out << *ts << '\n';
 			numTriples++;
 		}
 		cerr << numTriples << " results in " << st << endl;