Viewing battlefields (and the map landscape editor).

The editor currently only handles landscapes... I think we'll need to write just as much code for objects ))) because of definitions, rendering, and everything else, as well as object properties (we need to research the formats).
As for mirroring the landscape, it can be done by simply inserting arrays of saved cells with reversed indexing (perhaps also applying mirror mirroring to the mirrors), but it's not implemented yet. I think I'll add it in the next version.