Produce a whole bunch of debug info when terrains fail

Whenever people hit that h>=0 assert, we have no idea what really happening. This throws a bunch of info about the current terrain into stderr.txt to help debug it.

Sample output:

```
GetHeight({ 0.567496, -0.715613, -0.407243 }) returned 0.000349
Terrain state dump:
  Height fractal: MountainsNormal
  Color fractal: EarthLike
  Detail: fracnum 0  fracmult 1.000000  textures true
  Config: DetailPlanets 2   FractalMultiple 2  Textures  1
  Seed: 43
  Body: New Hope [1,-1,-1,0,3]
  Fracdefs:
    0: amp 1.000000  freq 4.664804  lac 2.000000  oct 8
    1: amp 0.000000  freq 85041.799995  lac 2.000000  oct 4
    2: amp 0.000000  freq 7886.079270  lac 2.000000  oct 1
    3: amp 0.000020  freq 1305.781353  lac 2.000000  oct 7
    4: amp 0.080000  freq 850.418000  lac 2.000000  oct 7
    5: amp 0.200000  freq 85.041800  lac 2.000000  oct 10
    6: amp 0.500000  freq 8.504180  lac 2.000000  oct 10
    7: amp 0.500000  freq 2.184295  lac 2.000000  oct 12
    8: amp 1.000000  freq 1.897802  lac 2.000000  oct 13
    9: amp 0.000000  freq 0.000000  lac 0.000000  oct 0
```