function stretch (arrayToStretch, sizeToStretch, dimToStretch) {
  return concat(...Array(sizeToStretch).fill(arrayToStretch), dimToStretch)
}
Stretches a matrix up to a certain size in a certain dimension
@param {Array} arrayToStretch
@param {number[]} sizeToStretch
@param {number} dimToStretch
@returns {Array} The stretched array