[Freeciv-Dev] Terrain flags

[Tomasz Wegrzanowski <maniek@xxxxxxxx>]

Here is a patch that introduces terrain flags.
For now there are 3 of them:
  Land, Ocean, SweetWater
Land is to mean : Land units can be there
Ocean is to mean : Naval units can be there
  (every tile is to have exactly 1 of these 2).
SweetWater is to mean : (This tile)/(Tiles next to it) can be irrigated

They of course don't work now. (full functionality will go to 1.12)
It is only proc for reading flags from terrain rulesets.