Enviro: good default values for the parameters dialog

1. In the Startup Dialog, select just the "Big Island of Hawai`i"
2. Click "Edit Properties"
3. Observe the parameters.  A basic Terrain Filename, and a basic Single Texture always appear as a default. For example, for Hawai`i, Terrain Filename will be "island_1k.bt", and Single Texture will be "bigisland_ls_1024.bmp".
4. Observe the rest of parameters.  They should be similar to the values below.
   • Terrain Filename: island_1k.bt
   • Vertical Exaggeration: 1.2
   • Regular terrain: not selected
     • subsample ratio: 4
     • suppress land: not selected
   • Dynamic LOD terrain: selected
     1. algorithm: McNally
     2. triangle count: 15000
     3. use triangle strips: selected
     4. detail texture: not selected
   • Min height above ground: 50
   • Navigation speed: 800
   • Texture: Single Texture
     • filename: bigisland_ls_1024.bmp
     • Mipmap terrain: selected
     • Request 16-bit: selected
     • precompute lighting: selected
     • pre-lit: selected
   • Sky Dome: selected
   • Ocean Plane: not selected
   • Artificial Horizon: selected
   • Trees: not selected
     • Size exaggeration: 30, visibility distance: 15
     • tree spacing 100, scarcity 0.0004
   • Roads: not selected
     • Texture map roads: selected
   • Buildings: not selected
5. Press OK to close the Terrain Creation Parameters dialog
6. Press OK to launch Enviro