Increase slowmover and reduce instability

These two changes go in opposite directions and it
seems that the combination is stronger than original.

Here are the positive tests at various TC:

15+0.05
LLR: 2.96 (-2.94,2.94) [-1.50,4.50]
Total: 24561 W: 4946 L: 4772 D: 14843

60+0.05
LLR: 2.96 (-2.94,2.94) [0.00,6.00]
Total: 15259 W: 2598 L: 2423 D: 10238

40/30
LLR: 2.96 (-2.94,2.94) [-3.00,3.00]
Total: 2570 W: 527 L: 422 D: 1621

Unfortunately there is also a bad result
with one sec time increment that needs
to be further investigated:

12+1
LLR: -2.97 (-2.94,2.94) [-3.00,3.00]
Total: 2694 W: 438 L: 543 D: 1713

bench: 8340585

src/timeman.cpp

@@ -78,7 +78,7 @@ namespace {
 
 void TimeManager::pv_instability(double bestMoveChanges) {
 
-  unstablePVExtraTime = int(bestMoveChanges * optimumSearchTime);
+  unstablePVExtraTime = int(bestMoveChanges * optimumSearchTime / 1.4);
 }
 
 

src/ucioption.cpp

@@ -83,7 +83,7 @@ void init(OptionsMap& o) {
   o["Emergency Base Time"]         = Option(60, 0, 30000);
   o["Emergency Move Time"]         = Option(30, 0, 5000);
   o["Minimum Thinking Time"]       = Option(20, 0, 5000);
-  o["Slow Mover"]                  = Option(50, 10, 1000);
+  o["Slow Mover"]                  = Option(70, 10, 1000);
   o["UCI_Chess960"]                = Option(false);
   o["UCI_AnalyseMode"]             = Option(false, on_eval);
 }