Using _vectors_ as fundamental datatype could make for a really neat experience.

Imagine e.g.:

* fundamental arithmetic operations that apply to both vectors and scalars
* implicit component-wise or vector-wise operations
* scalar values as 1D vectors
* higher order functions to manipulate those vectors
    * `map` function that applies a (quoted?) word to all vector elements and returns the result
    * efficient parallel operations
* a rich library of vector manipulation functions
* or even: matrices as a fundamental datatype?
    * problem: probably harder to conveniently enter via a 1-D repl
* sound more and more like a RPN version of APL…

Back to reality, here is what this prototype actually adds:

* new `DList!int` based datatype alongside the existing int, string and bool types
* basic support for printing such values in a readable fashion
* new fundamental `:` word that constructs a vector of two elements
    * `1 2 :` yields `[1, 2]`
* adapted `+` and `*` to support component-wise operations
    * `1 2 : 3 +` yields `[4, 5]`