Geo Referenced Raster Map Layer (Operation Gremlin) vikgrmlayer.c
Tasks:
*) read and understand World (JGW,etc) files.
*) new layer type, world data inside later, on save written into viking file as JGW/whatever.
*) new layer dialog choose image and type in world data, or button "load from file"
*) reference to map. we sh/could also store whole map in memory. but there also must be a filename to write to viking file.
*) only draws on proper zoom level, or perhaps very very close to proper zoom level
*) right click -> go to this zoom level, goto corner or center of map, export to world file

Later Versions:
*) edit mode where we can move map, resize (really resize tracks), etc.
*) rotation
