Minor charges

- added icon
- removed starmap declaration (from last commit) as it breaks all sorts
of shit
Minor change: streamlined image resources

- removed 40x40 planet images; only the 100x100 images remain
- added backgroundimagelayout = stretch for each planet's panel so that
it can automatically shrink the 100x100 images into 40x40 for the star
system display.
Add: blackholes

Added blackholes that, right now, do absolutely nothing.  They eat a
starName but do not show up in the Search function.  Stars have a 15%
chance of being generated as blackholes, but a galaxy can only have a
maximum of galaxySize/2 (rounded down) number of blackholes.