Add examples for simulations

[almarklein]

Closes #49

• Do a simulation synced with the animation-loop, so you see every step.
• Do a simulation that runs at its own pace, seeing some steps.

[almarklein]

@kushalkolar @clewis7 let me know if this is clear, and if this covers the use-cases you had in mind. Let's leave this open for a while, so you can try this out in FPL, and we can improve the examples along the way.