Basic descriptive functions for arrays are missing

[wegendt-bosch]

As a programmer I expect some basic functions over lists:

• min(x : array<T>) : optional<T> where T is int32, uint32, float finds the minimum of a list of numbers
• minArg(x : array<T>) : optional<uint32> where T is int32, uint32, float finds the index of the minimum member of a list of numbers
• max(x : array<T>) : optional<T> where T is int32, uint32, float finds the maximum of a list of numbers
• maxArg(x : array<T>) : optional<uint32> where T is int32, uint32, float finds the index of the maximum member of a list of numbers
• mean(x : array<float>) : float computes the mean of all values in a list
• std(x : array<float>) : float computes the standard deviation of all values in a list