Fixed Planets in Network game

[schuellerf]

Random planet numbers are mixed up with blackholes...
Removing random to avoid unintended blackholes in network game

Although I didn't understand why there is a random in the first place :-(

also added command line parameters and first draft for playernames

[ryanakca]

Thanks Florian! I'll try to take a closer look at some point over the next week or two. If I forget, please don't hesitate to give me a nudge.

[HAL20000]

I was also writing a patch for the disappearing planets in network mode. IMHO the randomness in planet.py is necessary if you want to use all the different planet sprites that are available (8 many) and not only the MAX_PLANETS-many accesible in the way @schuellerf coded it.

I hope, I can submit a merge request in a few days or so with my patch which also resolves the issue of disappearing plantes while still accessing all 8 sprites.