Reevaluate benchmark scene

[hepfnepf]

Following things might be improved:

• Expose the scene to the user, to let them thest the results of graphic changes
• Currently, there are no graphic settings, so it does not make that much sense yet
• Allow to change the order of benchmarks and wich ones to perform
• Maybe rather test how many fps ones have, than test how many enemies it take to get below 60fps
• Reevaluate the architecture. Maybe use individual sceens for each benachmark run. Could also help to unify the point above with the current mode