Be more aggressive on trying to finish iterations

Increase MaxRatio to use more time when in trouble.

After 16000 games at 60+0.05
ELO: 4.89 +-5.4 (95%) LOS: 99.9%
Total: 16000 W: 2700 L: 2475 D: 10825

No functional change.

src/timeman.cpp

@@ -29,7 +29,7 @@ namespace {
  /// Constants
 
  const int MoveHorizon = 50; // Plan time management at most this many moves ahead
- const float MaxRatio = 3.0f; // When in trouble, we can step over reserved time with this ratio
+ const float MaxRatio = 7.0f; // When in trouble, we can step over reserved time with this ratio
  const float StealRatio = 0.33f; // However we must not steal time from remaining moves over this ratio