Change the GalacticView to use a hi-res colour galaxy bmp by Baobobafet
Replace the galaxy.bmp to galaxy_dense.png and then optimise the GetSectorDensity method.
Fixed using the wrong pointer type float to float[]
Switch back using a bmp since OSX will apparently load the galaxy differently apparently!
Add a comment explaining why it must be a bitmap and change to use the SDL_LoadBMP_RW to emphasise the point.
Merge remote-tracking branch 'fluffyfreak/galaxy_refactor'