Renamed cFinishGenSingleBiomeSingleTopBlock to cFinishGenSingleTopBlock

Now accepts a vector of biomes and a vector of allowed blocks.
Also the deadbushes finisher generates in mesa biomes as well.
More like:
```cpp
for (int idx = 0; idx < ARRAYCOUNT(m_IsAllowedBiome); ++idx)
{
  m_IsBiomeAllowed[idx] = false;
}
```