Restore writeFrame method in ObserverSwarm

[SFRailsback]

ObserverSwarm –writeFrame: un-comment the block “if([habitatRasterList getCount] > 0)”. Uncomment “id raster = nil;”.
ObserverSwarm –buildObjects: after this statement:
[habitatRasterMap at: habitatSpace insert: polyWorldRaster];
add this one: [habitatRasterList addLast: polyWorldRaster];

Submitted for inSTREAM too.

[SFRailsback]

This repair was made and it works in Windows. For some reason the writeFrame method does not work in Fedora for me, for this model or others -- it raises an X windows error at the PixMap createEnd statement. It does work in Ubuntu. I assume the problem is with my Fedora, not our code.