setCurrentLayer (name) {
    const layer = this.layer_map[name]
    if (layer) {
      if (this.current_layer) {
        this.current_layer.deactivate()
      }
      this.current_layer = layer
      this.current_layer.activate()
      return true
    }
    return false
  }
Sets the current layer. If the name is not a valid layer name, then this
function returns `false`. Otherwise it returns `true`. This is not an
undo-able action.
@param {string} name - The name of the layer you want to switch to.
@returns {boolean} `true` if the current layer was switched, otherwise `false`