Config-Value Check

[lapplislazuli]

At the moment, the configuration is "just" checked by compiler.
However, some things are ok with types but not ok with the algorithms, e.g. declaring a negative or zero population is "valid" at the moment.

I think it would be nice if we have for our Config a check valid :: Config -> Bool that defaults to true, but we can add all constraints that we gather.
Also it should give an error message what is wrong, so maybe something valid :: Config -> [Errors] that can be printed.

I think it makes more sense to have this

1. centrally checked and per config defined
2. before any computation / compilation is done - i do not want to wait for precompute fixes to finish to see that my genetic config is failing