parser.segmentation_layers (etc.) ought to have a way to exclude archived layers

[JoeStrout]

In my use case, the state has a large number of segmentation layers that have been archived. In the following example, the second layer is archived, but the first is not.

{
      "type": "segmentation",
      "source": "precomputed://gs://dkronauer-ant-001-manual-labels/synapses/662836af010000d9004072c2/postsynaptic-terminal/000",
      "tab": "annotations",
      "segments": [],
      "name": "72c2"
    },
    {
      "type": "segmentation",
      "source": "precomputed://gs://dkronauer-ant-001-manual-labels/synapses/66283935010000cd004072c5/postsynaptic-terminal/000",
      "tab": "source",
      "segments": [],
      "name": "72c5",
      "archived": true
    },

It'd be nice if nglui.parser.segmentation_layers(state) had an optional parameter to specify whether to exclude these archived layers. (And similar for any other layer types.)