Some macros in the file Sim.cpp are never used.

Some macros in the file Sim.cpp is never used,

```
#define LEDGER_CONVERGE 4 
#define LEDGER_FORCE_CONVERGE 7
#define AV_MIN_CONSENSUS 50
#define AV_AVG_CONSENSUS 60
#define AV_MAX_CONSENSUS 70
```

what are they meaning and shouldn't we set a threshold for a time-consuming transaction to increase the the efficiency of the network?
