Refactor the terminal Vuex module

[dhruvkb]

Currently the Vuex module for the terminal uses old style functions

name: function (argOne) {
  return function (argTwo) {
    ...
  }
}

which should, for reasons such as terseness and readability, be replaced with

name: argOne => argTwo => {
  ...
}

across all getters and mutations, essentially the entire module.

[dhruvkb]

This has been implement in 8f1bed5.