n-body Benchmark

[DrSloth]

One possible way to speed up the language would be to use VecDeque instead of Vec, but the efficiency implications of that have to be explored

[DrSloth]

I am going to implement the nbodies benchmark in various versions. As soon as everything is done for the benchmark it will also be implemented eitg dicts (as soon as they are ready) and later on with structs (if they are accepted as a feature)