Changed Dict(ks,vs) to behave like Dict(zip(ks,vs))

Currently the lenght of `ks` is used to deterimine the numer of elements in the dictionary. After this, the shortest of `ks` and `vs` is used.

An alternative might be to throw an error if they are not equal length, but I think the same behavior as `Dict(zip(ks,vs))`, is the most intuitive.