Reduce granularity when stepping through Thermo

[leogott]

Currently when stepping through a solution, the solver makes one step for each value eliminated in a thermometer. Example: Hidden single 9 in Row 1 r1c2 Thermometer at r1c3: Cleared values 8 from r3c2 Thermometer at r1c3: Cleared values 7 from r3c3 Thermometer at r1c3: Cleared values 6 from r2c3 Thermometer at r1c3: Cleared values 5 from r1c3

However when a hidden single is found on the thermometer, these values are eliminated all in one step.

Imo it would make sense to have these steps be a single step, e.g. "Thermometer at r1c3: Cleared higher-or-equal values downwards (4x)"